US3301012A - Circular knitting machines for the production of hosiery with double, outwardly turned-over welts - Google Patents

Description

Jan. 31, 1967 TENCONI 3,301,012

CIRCULAR KNITTING MA NES FOR THE PRODUCTION OF HOSIERY WITH DOUBLE, OUTWARDLY TURNED-OVER WELTS Filed Dec. 24, 1964 6 Sheets-Sheet 1 i s Y x 10 N 4 Jan. 31, 1967 R TENCONl 3,301,012

CIRCULAR KNITTING MACHINES FOR THE PRODUCTION OF HO'SIERY WITH DOUBLE, OUTWARDLY TURNED-OVER WELTS Filed Dec. 24, 1964 6 Sheets-$heet 2 INVENTOR.

R. TENCONI nFan. 31, 1967 CIRCULAR KNITTING MACHINES FOR THE PRODUCTION OF HOSIERY WITH DOUBLE, OUTWARDLY TURNED-OVER WELTS Filed Dec. 24, 1964 6 Sheets-Sheet 5 INVENTOR.

Jan. 31, 1967 R. TENCONI 3,301,012

CIRCULAR KNITTING MACHINES FOR THE PRODUCTION OF HOSIERY WITH DOUBLE, OUTWARDLY TURNED-OVER WELTS Filed Dec. 24, 1964 6 Sheets-Sheet 4 I NVEN TOR.

R. TENCONI Jan 31, 1967 CIRCULAR KNITTING MACHINES FOR THE PRODUCTION OF HOSIERY WITH DOUBLE OUTWARDLY TURNED-OVER WELTS Filed D90. 24, 1964 6 Sheets-Sheet 5 INVENTOR.

Jan. 31, 1967 R. TENCONI 3,301,012

CIRCULAR KNITTING MACHINES FOR THE PRODUCTION OF HOSIERY WITH DOUBLE, OUTWARDLY TURNED-OVER WELTS Filed Dec. 24, 1964 6 Sheets-Sheet 5 33 23b A \u JIM/1,, 3

INVENTOR.

lie in the additional grooves of the related sinkers.

United States Patent (IHRCULAR KNITTHNG MAQHINES FUR THE H29- DUCTKUN @F HQSIERY WITH DGUBLE, GUT- .WARDLY TURNED-OVER WELTS Riccardo Tenconi, Varese, Italy, assignor to Marcella Sessa, Varese, Italy Filed Dec. 24, W64, Ser. No. 420,955 Claims priority, application Italy, Jan. 3, 1964, 179/64 8 Claims. Cl. 664ll) This invention relates to circular knitting machines for the production of hosiery, such as stockings and socks, with double, outwardly turned-over tops or welts.

Various arrangements have been proposed for eliminating the transfer bits, the dial in which they are supported and the respective driving means, which devices have been used in conventional circular knitting machines for the production of double, inwardly turned-over welts. In all of these previously proposed arrangements, the regular knitting needles are used for the production of the double welt and are alternately formed with long and short butts and special sinkers are employed which have an additional groove below the usual knitting level or ledge to form a lower ledge. In all of these proposals, the loops of the first course, or of a few initial courses, are held so low on the needle shafts during the formation of the double welt by the additional grooves of the sinkers that they cannot be cast off, and these retained loops are then released, after the welt is completed, to knit the released loops together with a further course.

In a known machine of the above type, the thread for the formation of the first course of the welt is fed to all needles and, in order to ensure that the loops of the initial course on alternate needles are not cast off during the formation of the following courses, these loops are so lowered on the respective needles that they come to In order to operate in the foregoing manner, a selective control is provided for the sinkers by means of which either alternate sinkers or all sinkers can be actuated, that is, retracted radially .outward. Since circular knitting machines usually do not have a pattern device which is capable of effecting such selection of sinkers, an addi tional control is required leading to considerable complication in the construction of the machine, and further there is no assurance that the alternating loops of the first course will be held low on the respective needles.

In order to avoid the above disadvantages, another proposal has been made, based on the same fundamental principle, and according to which one or more initial courses of welt are formed on the lower cast-otf ledges of the special sinkers while all other courses of the welt are formed on the regular or upper cast-off ledge and joined with the, initial courses formed on the lower castoff ledge of the sinkers by a connecting course, and, finally, the courses held down by the additional grooves of the sinkers are connected with the last course of the welt and the remaining parts of the stocking are subsequently knitted in the usual Way.

In a machine capable of operating in the manner de-- scribedimmediately above, there are provided selectively engageable and disengageable additional cams. One ad ditional cam is associated with the knitting cam portion of the needle cams and the other additional cam is associated with the cam portion for effecting the outward movement of the sinkers for the purposes of increasing the downward movement or withdrawal of the needles and the outward movement of the sinkers, respectively, so as to selectively effect the formation of stitches on the lower or on the upper cast-off ledges of the sinkers. Further, the profiled guide-ring for the needle butts lifts the needles insufiiciently to engage the thread fed by the thread guides, and a lifting cam is provided which can be engaged or made operative by a suitable control to lift the needles sufficiently for release of their latches and for engagement with the thread fed by the thread guides. This lifting cam is controlled so that it acts only on the long butt needles during the formation of the first course, at which time the additional cams associated with the knitting cam portion and the sinker cam are also engaged or operative. The lifting cam also acts only on the long butt needles during the formation of the next course, at which time the additional cam associated with the sinker cam is inoperative. The lifting cam, acts if necessary, on all needles during the formation of a course following this latter course, while it is again inactive for the short butt needles during the formation of the course following the last mentioned course, after which it is finally engaged to act on all needles. The additional cam associated with the knitting cam portion is controlled so that it is operative for all needles during the formation of the initial course or courses together with the additional cam associated with the sinker cam, so that it remains active for a part of the needles during the formation of at least one course following these initial courses, and so that it is subsequently made inactive for all needles.

In a machine of this type it is also known to use the regular stitch-widening device in order to permit the formation of stitches in the course in which the additional sinker cam is already inactive and the needle lifting cam acts only on the long butt needles, that is, in the course following the connecting course between the courses respectively formed on the lower cast-off ledges and the upper cast-off ledges of the sinkers. The result achieved by the stitch-widening device can be alternatively achieved by leaving the additional cam associated with the withdrawing or knitting cam engaged in the respective course.

Even though the last described machine, when operated as above, is reasonably reliable in its production of the double welt, it has been found in practical operation that there remains some danger of thread breakages, due to excessive tensions, particularly at the critical moment of the connection of the courses formed on the lower and upper cast-off ledges of the sinkers. Further, difficulties are encountered in the production of those parts of the stocking, such as the heel and toe, which are knitted with an oscillating movement of the needle cylinder. Such difficulties are due to the presence of the additional cam associated with the withdrawing or knitting cam for the needles.

As is known, during the production of the heel and toe of the stocking, the needles, after having been lowered by the withdrawing or knitting cam, must be raised again practically immediately and may only remain in the lowered position for a short time. However, if an additional cam is provided in association with the withdrawposition before they can be lifted again.

It is an object of the invention to eliminate the above disadvantages of the known arrangements provided in circular knitting machines for the production of hosiery with double, outwardly folded over welts, without requiring the use of transfer bits.

A further object is to avoid the danger of thread breakages, and to ensure that difiiculties or imperfections will not arise during the knitting of stocking parts other than the double welt by reason of those elements provided in the knitting machine for the knitting of the double welt.

The solution to this problem in accordance with this invention is based on the finding that it is not necessary to form the first courses, which are held down by the lower additional grooves of the sinkers during the production of the welt, on additional lower cast-off ledges of the sinkers, but that it is only necessary that these initial courses be at the level of the lower sinker grooves at the moment when the knitting machine starts to form the connecting course between the initial courses and the following courses. Thus, according to the invention, the stitches are always formed on the same cast-off ledges of the sinkers below which the latter have additional or lower grooves, and at least two initial courses are formed at first and then lowered to the level of the additional grooves of the sinkers, whereupon a connecting course is formed between the lowered initial courses and the following courses.

The above operations are practically performed by a circular knitting machine which is provided with needles alternately having long and short butts, special sinkers with additional bottom grooves below the usual cast-off ledges, a lifting cam for the needles which can be selectively controlled so that it only lifts the long butt needles or all needles so far that the needle latches are released and the needles can engage the new thread fed by the thread guides, as well as additional cams in the needle and sinker cam assemblies which can be activated by suitable controls in order to respectively extend the downward movement of the needles and the radially outward movement of the sinkers as compared with the usual downward movement of the needles and outward movement of the sinkers.

According to the invention, the additional cam in the needle c-am assembly is displaced, in the direction of the normal needle cylinder rotation, from the lowest point of the withdrawing or knitting cam, and the profile or guide ring for the needle butts is provided with a step between the lowest point of the withdrawing cam and the additional cam, so that the needles lowered by the withdrawing cam can be lifted immediately by such step.

The additional cam in the sinker cam assembly is likewise displaced, in the direction of the normal needle cylinder rotation, from the regular sinker cam portion effecting the outward movement of the sinkers, and this additional cam is controlled so that it acts on all sinkers during the formation of a single course which follows at least one initial course and precedes the connecting course, at which time the additional cam associated with the withdrawing or knitting cam acts on the long butt needles.

In a particular embodiment of the invention, the additional cam in the needle cam assembly not only functions to lower the initial courses before the connecting course is formed, but also serves to adjust the width of the stitches, to which end this additional cam is vertically displaceable by means of a separate control. In this case, the additional cam of the needle cam assembly replaces the regular stitch-widening device, which consists, as is known, of means for lifting and lowering the entire needle cylinder.

The above, and other objects, features and advantages of the invention, will be apparent in the following detailed description of illustrative embodiments thereof which is to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic, vertical sectional view of a circular knitting machine of a type that may embody this invention;

FIG. 2 is a developed view of the needle cam assembly of a machine embodying this invention;

FIG. 3 is a developed view of the sinker cam assembl FIG. 4 is a bottom view of the sinker cam assembly;

FIG. 5 is a detail sectional view taken along the line VV of FIG. 4;

FIG. 6 is a perspective view of a device for actuating the additional cam for the sinkers;

FIG. 7 is a perspective view of a device for actuating the additional cam for the needles;

FIG. 8 is a side e-levational view of a sinker used in the circular knitting machine embodying this invention;

FIG. 9 is a diagrammatic view of several sinkers and needles during a phase of the formation of the double welt of a stocking;

FIG. 10 is a schematic view on an enlarged scale, of the stitch pattern of the first courses obtained during the operation illustrated on FIG. 9;

FIG. 11 is a view similar to FIG. 9, but illustrating a phase in the formation of the double welt according to a modified method of operation;

FIG. 12 is a schematic view, on an enlarged scale, of the stitch pattern of the first courses as obtained by the method of operation illustrated on FIG. 11;

FIG. 13 is a schematic developed view of the upper parts of several needles and of the corresponding sinkers which are situated in the region of the knitting cam and the additional cam of the needle cam assembly; and

FIG. 14 is a diagrammatic view showing the arrangement of the needles in the needle cylinder and of the sinkers in the sinker supporting ring.

The drawings show only those parts of a conventional circular knitting machine for the manufacture of hosiery which are absolutely necessary for understanding the invention. Naturally all other parts of the knitting machine, which are neither illustrated nor described, are conventional and can be constructed so as to operate in a manner consistent with the corresponding parts of existing circular knitting machines. In order to simplify the specification and drawings, the invention is disclosed herein as being embodied in a single-feed machine, but it is to be understood that the invention may be similarly applied to machines having a plurality of feeds.

Referring to FIG. 1 in detail, it will be seen that the circular knitting machine there shown essentially comprises a cylinder 1 having a sinker supporting ring 2 secured on its upper end portion. Latch type needles 3 are vertically movable in axial grooves formed in the outer surface of cylinder 1, and the needles are held in the related grooves by the turns of a surrounding helical spring 4.

Sinkers 5 are displaceable in radial grooves of the sinker supporting ring 2 and are surrounded by a spring ring 6 which urges the sinkers radially inward. The cylinder 1 is secured on a tubular sleeve 7 which is rotatable in the machine frame 8 and provided with an outer ring gear 9 which meshes with a spur gear 10. Gear 10 is secured on a shaft 11 journaled in the frame 8, and which is driven by a motor (not shown). Arranged coaxially around the lower part of sleeve 7 is a main control drum 12 which is suitably turned and controls the entire cycle of the knitting machine in the usual manner.

A ring 13 is secured on the machine frame above the sinker supporting ring 2 and carries the cam for controlling the sinkers 5. FIG. 1 shows also a thread guide arm 14 which feeds the thread to a point in the vicinity of the upper edge of the needle cylinder where it can be engaged by the needles 3. Fixedly supported about the needle cylinder 1 is the cam assembly 15 for controlling the needles 3.

The machine parts described above correspond to those generally provided in all known circular knitting machines for the production of stockings and socks and the operation thereof is similarly well known.

Specially designed sinkers are used in the machine according to the invention, and such sinkers may have, for example, the configuration shown on FIG. 8. Each sinker has a shortened cast-off ledge 17 and an additional nose 18 under the regular nose 19. The two noses form a bottom groove or notch 20 under the nose 18 and an upper groove 21 between the noses 18 and 19. Each sinker 5 further has a stop 22 for the spring ring 6 to act against a butt 23 and a guide notch 24..

The major proportion of the sinkers inserted in the radial grooves of the sinker supporting ring 2 have a short butt 23a and only a small number of the sinkers, which are all grouped together, have a long butt 2317, as represented schematically on FIG. 14, where the sinker butts 23a and 23b, which actually extend upwardly, are shown developed in a horizontal plane. The reasons for these different lengths of the sinker butts will be explained more fully below.

FIG. 2 shows some of the most important cams of the assembly 15 for controlling the needles 3. The illustrated cams include the central upper cam 26 and the withdrawing or knitting cam 27 which, in the present case, is positioned to act on all of the needles during the production of the entire stocking. An additional cam 29 is provided to effect downward movement of selected needles when disposed in certain operative positions, and a lifting cam 30m is operative to lift the needles, so that the latter release their latches and are brought to a level where they can engage the thread fed by the thread guide arm 14. Finally, a profiled guide ring 32m is provided to slidably support the butts of the needles 3. This guide ring 32m is vertically positioned to lift the needles, after the downward movement or withdrawal, to a vertical position where they neither release the needle latches nor are the needles engageable with the thread fed by the thread guide arm 14. When the needle butts bear on the guide ring 32m, the hooks of the needles are about at the level of-the upper part of the sinkers.

The arrow 33 on each of FIGS. 2, 3, 13 and 14 indicates the normal direction of motion of the needles relative to the cams during the continuous rotation of the needle cylinder 1. In FIG. 2, those cams have been omitted which operate during the oscillating movement of the needle cylinder, as during the knitting of the heel and toe.

As can be seen from FIG. 2, the additional cam 29 provided in accordance with this invention is displaced in the direction of the arrow 33, that is, in the direction of normal rotation of cylinder 1, from the lowest point of the withdrawal or knitting cam 27 and the guide ring 32m has a step 31 between the lowest point of the cam 27 and the additional cam 29. Thus, the needles lowered by the cam 27 are lifted to a certain extent by the step 31 before they can be lowered further by the additional cam 29 assuming that the latter is operatively positioned to engage the butts of the needles in question.

Each needle has a butt-34, and these butts are of four different lengths. The needles are arranged in the grooves formed in the outer surface of cylinder 1 so that relatively long and short needle butts are alternated whereby a certain selection of the needles is possible, as will be explained below. In order to permit the engagement and disengagement of the cams 29 and 30111 by radial movement thereof toward and away from the circumference of the needle cylinder, the needles in a limited zone or group are provided, in a known manner (FIG. 14) with long butts 340 which are longer than the long butts 34a of the needles in the rest of the needle set, and with short butt-s 34d which are shorter than the short butts 34b of the needles in the rest of the needle set. It should be noted, however, over the entire circumference of the needle cylinder a needle with a relatively longer butt 34a or 340 always alternates with a needle with a shorter butt 34b or SM.

Each of the cams 29 and 30m can be individually con- I to its highest point.

trolled to assume different positions, that is, different radial distances from the outer surface of the needle cylinder. The cam 29 is controlled to take any one of five different positions: In a first position cam 29 is inactive for all needles; in a second position cam 29 acts only on the needles with the longest butts 340; in a third posi tion cam 29 acts on all needles with long butts, that is, both on those with long butts 34c and on those with long butts 34a; in the fourth position cam 29 acts on the needles with the butts 34a, 34b, and 340; and finally in a fifth position it acts on all needles, including those with the shortest butts 34d. The cam 39m can only assume three positions. in a first position it acts on all needles; in a second position it only acts on the needles with butts 34a, 34b and 34a; and, in a third position, it is inactive with respect to needles with short butts 34b and 34d and, therefore, only acts on the needles with long butts 34a and 34b.

The cam 29 is not only displaceable radially toward and away from the circumference of the needle cylinder, but it is also vertically movable to permit variations of the stitch width by means of this cam.

FIG. 7 shows schematically a suitable device for controlling the cam 29, and a similar device can be used for controlling the cam 30m. The control device for cam 29 is actuated by steps 35 and 36 on cam rings 37 and 38 carried by the contnol drum 12. The ring 38 is contacted by the nose of a feeler lever 40 which is secured on a shaft 42 journaled in the machine frame. The shaft 42 carries an arm 44 which is in contact with a pin 46a on a slide 46 which has the cam 29 extending therefrom in the direction radially toward cylinder 1. The cylindrical shell of cam assembly 15 has a suitable opening (not shown) through which the cam 29 can extend more or less into the path of the needle butts. A spring 45 holds pin 46a in contact with arm 44 and consequently urges the nose of the lever 40 against cam ring 38.

When the nose of feeler lever 40 is in contact with the ring 38, as shown on FIG. 7, the cam 29 is in the position closest to the circumference of the needle cylinder. However, when drum 12 is turned to engage the cam steps 36 with the nose of lever 40, cam 29 is displaced radially outward from the circumference of the needle-cylinder. Since the stepped cam 36 has four steps, this radially outward displacement can move cam 29 to four different positions. In the first of these displaced positions cam 29 is made inactive only for the needles with short butts 34a; in the second displaced position cam 29 is made inactive for all needles with short butts 34b and 34d but remains active for the needles with long butts 34a and 340; in the third displaced position cam 29 is made inactive for the needles with the ibutts 34b, 34c and 34d; and, in the fourth position, caused by engagement of lever 40 with the highest step of cam 36, earn 29 is inactive with respect to all needles.

The slide 46 is guided between two stationary, horizontal pins 56 and 57 so that it can rock about a horizontal axis between the pins 56 and 57, in addition to being displaced longitudinally. Such rocking movement of slide 46 is controlled by the cam ring 37 on drum 12.

In contact with the ring 37 is the nose of a feeler lever 39 which is secured on a shaft 41 journaled in the machine frame. Shaft 41 also carries an arm 43 which has an adjusting screw 50 extending through its free end portion. This screw is in contact with one arm of a bell-crank 58 which is pivoted at 58a and has its other arm hearing from above on the slide 46. The slide 46 is urged upwardly into contact with the bell-crank 58 by a spring 65.

When the nose of the lever 39 rides on the ring 37 of the drum 12 (as shown on FIG. 7), the cam 29 is lifted However, when the nose of lever 39 is engaged by the cam 35 on ring 37, the cam 29 is displaced downwardly to an extent dependent on the radial height of the cam 35 at the point of its contact by lever 39.

7 Referring now to FIGS. 3 and 4, it will be seen that the sinker cam ring 13 has an annular, downwardly opening cam groove 47 receiving the butts of the sinkers which are of different height, as mentioned above, a larger group or zone of sinkers being provided with shorter butts 23a, and a smaller group or zone of sinkers having taller butts 23b. The annular groove 47 has a cam portion 48 for displacing all of the sinkers radially outward to a certain extent. Displaced circumferentially from the cam portion 48 in the direction of the arrow 33 is an additional cam 49 which can be inserted from above into groove 47, and which is then operative to cause an outward movement of the sinkers that is greater than that caused by the cam portion 48. The division of the sinkers into a group with short butts and a group with long butts is for the purpose of permitting the engagement and disengagement of the additional cam 49.

The additional cam 49 is secured on a stirrup 51 pivoted at 52 on the machine frame (FIGS. and 6). A spring 53 acts on stirrup 51 to urge the latter in the direction for introducing the additional cam 49 from above into a recess of the annular groove 47. The stirrup 51 bears on a profiled ring 54 which is angularly displaceable on the sinker cam ring 13. The ring 54 has, on its upper edge, a two-step cam 55. The first step of cam 55 lifts the stirrup 51 and the cam 49 so that the latter becomes inactive for the sinkers with short butts 23a, while the second step of cam 55 lifts the cam 49 to a position in which it is inactive for all sinkers. When the stirrup 51 bears on the ring 54 under the action of the spring 53, the additional cam 49 is active for all sinkers.

The displacement of the ring 54 along a circular path on the sinker cam ring 13 is effected by the control drum 12 which is provided, for this purpose, with a two-step cam 59 (FIG. 6). The nose of a feeler lever 60 contacts the drum at the level of cam 59. The lever 60 is secured on a shaft 61 carrying an arm 62 having a forked free end which engages a pin 63 secured on the ring 54. A spring 64 acts on the arm 62 to urge the latter in the direction for urging the nose of the feeler ever 60 in contact with the surface of the drum 12. When the feeler lever 60 bears on the drum, the additional cam 49 is fully extended into cam groove 47 for engagement with the butts of all sinkers. When the nose of the feeler lever 60 is on the first step of cam 59, the additional cam 49 is inactive for the sinkers with short butts 23a. When the second step of the cam 59 engages the nose of lever 60, the additional cam 49 is elevated to a position in which it is inactive for all sinkers. In FIG. 5, the completely inactive position of the additional cam 49 is indicated by dot-dashed lines, while the cam 49 is shown on FIGS. 3 and 4 in its active position for all sinkers.

A possible method of operation of the circular knitting machine for the production of the double welt of a stocking will now be described with a reference to FIG. 9. In this view of the drawings, there is a schematic representation of one of the sinkers 5 shown partly broken away, and of several needles 31, 311, 3111, 31V, 3V, 3V1 and 3VII which cooperate to form the knitted fabric. The courses of the knitting are designated by the capital letters A, B, B and C. The needles 3-I, 3-III, 3V and 3-VII have long butts 34a or 340 and the needles 3-II, 3IV and 3-VI have short butts 3412 or 34d.

For the production of the first course A at the start of the welt, the lifting cam 30m in the needle cam assembly is postioned so that it can act only on the long-butt needles 3-I, 3-III etc.

This setting is achieved as follows: At the end of the production of the preceding stocking the lifting cam 30m is positioned so as to act on all needles. Before the start of the production of the first course of the new stocking, the lifting cam 30m is displaced radially outward from the needle cylinder, at a time when the cam 30m is being passed by the zone including needles with short butts 34b, s-uch displacement of the cam 30m being to the postion Where is can no longer act on the needles with short butts 34d. When the zone of the needles with short butts 34d passes the cam 30m, the latter is moved further outward so that it becomes also inactive for the needles with short butts 34b. Thus, the cam 30m is in a position in which it can act on only needles 3I, 3-III etc. with long butts 34a or 340.

Further, for the protection of the first course A, additional cam 29 is in its completely inactive position, or it can be engaged, as will be described below, to widen the stitches, and the additional cam 49 in the sinker cam assembly is positioned to be inactive for all sinkers. The formation of stitches with the long-butt needles is effected in the usual way on the cast-off ledge 17 of the sinkers and the first course A is laid into the upper grooves 21 of the sinkers.

For the formation of the second course B, the lifting cam 30m is moved radially inward to the position Where it can act on all needles. Such radially inward movement is effected in two steps as follows: When the zone of the needles with short butts 34d passes the cam 30m, the latter is moved radially inward toward the needle cylinder to lie just outside the butts 34d. When the needles with short butts 34b subsequently arrive at the position of the cam 30m, the latter can already act on these needles and can be then moved closer to the needle cylinder so that it can thereafter also act on the needles with short butts 34d.

This type of two-step (or multiple step) engagement of a cam is known in itself and, therefore, will not be described here in greater detail.

For the production of the second course B, the additional cam 29 is disengaged, if it has been previously engaged for stitch widening, and it is made inactive or brought into a position in which is causes a minimum widening of the stiches. Further, the additional sinker cam 49 remains disengaged and inactive for the production of course B. The production of the start of the stocking is thus continued in known manner on the cast-off ledges 17 of the sinkers.

The production of the following course B is effected in the same manner as the production of the preceding course B on the cast-off ledges 17 of the sinkers. However, the additional cam 29 is moved to the position where it can only act on the needles with long butts 34a and 340 and the additional sinker cam 49 is displaced to the position where it is active on all the sinkers. Such displacement of cam 49 is effected in two steps. During the passage of the sinkers with short butts 23a cam 49 is lowered so as to lie just above these butts, whereby the cam 49 can thereafter act on the butts 23b for displacing the related sinkers radially outward. While cam 49 engages butts 23b it is moved further downward so as to be finally positioned for engaging the sinker butts 23a. Thus, the course B is gradually moved down during its formation and, after the preceding course B has been deposited on the new stitches by the withdrawal of the needles caused by the withdrawing or knitting cam 27, and by the further downward movement of needles with long butts 34a and 340 which have been lowered by the additional cam 29, and which take along the corresponding stitches. Since the sinkers 5 are outwardly displaced at the same time by the additional cam 49 beyond the displacement effected by the regular sinker carn portion 48, the initial courses drop down and the stitches of the course B formed by the long-butt needles come to lie in the lower additional grooves 20 of the sinkers which are then immediately displaced radially inward by the cam groove 47 to retain the corresponding stitches of the course B in the lower grooves 20.

For the production of the following or connecting course C, the cams 30m and 29 remain in their existing positions, that is, with the lifting cam 30m positioned to act on all needles and the cam 29 positioned to act only on the needles with long butts 34a and 340, and the additional sinker cam 49 is returned to its inoperative position. The course C is formed, like the preceding course, on the cast-off ledges 17 of the sinkers. In order to ensure that the preceding lowered course B is con nected with the new stitches, the long-butt needles 3I, 3-III etc. are lowered by the additional cam 29 and also positioned to cause the formation of additional stitches. Consequently only those stitches of the course B formed with the long-butt needles 3-1, 3-III etc. are cast off on the corresponding stitches :of the course C and connect the courses formed subsequently on the cast-ofl? ledges 17 of the sinkers with thepreceding courses A and B which are held down by the lower grooves 2410f the sinkers.

Following the production of hte course C, there is obtained the stitch pattern represented schematically on FIGS. 9 and 10.

It isdesirable to note at this point the following advantages achieved with the invention:

During the production of the welt of a stocking, a particularly critical and delicate moment is that of the transfer from the course B preceding the connecting course to the connecting course C. This moment is critical due to the high tensions to which the thread is subjected when it is pulled'down by'the long-but-t needles acted on by the additional cam 29 for the formation of the connecting stitches. Particularly long loops must be formed which obviously require an increased thread supply.

FIG. 13 shows very clearly how this increased thread supply is provided according to the invention without subjecting the thread to excessive tension. In FIG. 13, the withdrawingcam 27 is shown active for all needles, while the additional cam 29 is shown acting only on the long-butt needles. The needles are shown in the positions that they assume at the end of the production of course B and at the start of course C. In FIG. 13', it is assumed that the short-butt needle 3-II is the last needle that forms the course B and that the long-butt needle 3-III is the first needle to form the cource C, with the needles moving in the direction of the arrow 33. All needles, after they have been lowered by the withdrawing cam 27, are lifted slightly by the step 31 on guide ring 32m. By reason of this slight lift of the needles, the loops tightened during the descent of the needles are left loose on the hooks of the needles, as can be seen clearly on FIG. 13. Since the short-butt needles 3 -11, 3IV etc. are not acted upon by the additionalcam'2 9, these needles move in lifted position past the cam 29 and thus do not tightly hold the respective loops. It follows therefore that the long-butt needles 3-III and 3'V acted upon by the cam 29 to pull the loops downwardly for establishing the connection find the necessary thread supply without excessive tensioning of the thread and the danger of breakag'es, since these are loose loops, bothbefore and behind each long-butt needle, from which the thread supply. for the long loop can be drawn.

In a modified method of production of the first courses of the welt according to the invention illustrated on FIGS. 11 and 12, and which permits a further reduction of the stress on the thread, the control of the cam 3m is selected so that only the long-butt needles are lifted by the lifting cam 30m during the production of the third course B In this case, the short-butt needles do not cast off the previously formed stitches (of course B) and do not engage the thread for the formation of course B The stitches held in low positons on the needle shafts of the short-butt needles 3-II, 3lV, etc. belong in this case to course B, and the stitches formed by the long butt needles are more easily cast off. In the modification of FIGS. 11 and 12, it is obviously essentially that course B be completed, whereas the course B could be omitted in the case illustrated by FIGS. 9 and 10.

The production of the courses follow the connecting course C and the connecting of the welt to the body of the stocking can be effected in any known manner and are not part of the present invention, so that such procedures need not be described in detail herein.

' It will be seen from the above that the additional cam 29 in the needle cam assembly 15 has the principal function, according to the invention, of pulling down the initial courses formed before the production of the connecting course C. In order to perform this function, it is necessarythat it cooperate with the additional cam 49 in the sinker camassembly. Since the additional cam 29 does not function as an extension of the regular withdrawing cam 27, it can therefore effect a less pronounced downward displacement of the needles and be spaced from the regular withdrawing cam 27. The spacing between cams 27 and 29 makes possible the arrangement of the step 31on the profiled guide ring 32m to lift the needles again immediately after they have been lowered by the cam 27. Further, the additional cam 29 can function as a stitch widening device to vary the stitch width in the different courses, particularly at the start of the production of the welt. It has been found in practice that particularly favorable results are obtained when the first course A is formed with wide stitches to impart elasticity to the stocking, the second course is formed with narrower stitches, the course B with regular wide stitches and the connecting course C with wider stitches than the third course B to make sure that the long-butt needles can cast off the stitches satisfactorily. In order to obtain these variations of the stitch width, it is only necessary to arrange cams 35 of corresponding height at suitable points on the ring 37 of the control drum 12. Although particular embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by One skilled in the art without departing from the scope or spirit-of the invention as defined in the appended claims.

What is claimed is: 1. In a circular knitting machine for the production of hoisery with a double, outwardly folded-over welt and which comprises a rotated cylinder carrying a set of latch type needles that are axially movable and alternately have long and short butts, radially movable sinkers located between the needles and each having a cast-off ledge and an additional radially opening groove below said ledge, a thread guide for feeding thread to the successive needles, a needle lifting cam engageable with said butts of the needles for raising the latter to a level at which the needles can engage thread fed by the guide, a needle withdrawing cam acting on the butts of the needles for effecting downward movement of the latter after engagement of the needles with the thread, a sinker cam ring controlling the radial movements of the sinkers and having a portion effecting radially outward movement of the successive sinkers upon said downward movement of the adjacent needles by said withdrawing cam: the combination of an additional needle cam spaced from the lowest part of said withdrawing cam in the direction of rotation of said cylinder and selectively engageable with the needle butts to effect downward movement of the needles beyond the lowermost position to which the needles are moved by said withdrawing cam,

an additional sinker cam spaced from said portion of the sinker cam ring in the same direction, and by a corresponding distance as said additional needle cam with respect to said withdrawing cam, said additional sinker cam being selectively engageable with the sinkers to effect radially outward movement of the latter beyond the movement thereof by said portion of the sinker cam ring,

means located between said withdrawing cam and said additional needle cam to effect slight lifting movement of the needles immediately following the downward movement of the needles by said withdrawing cam,

control means for said additional needle cam positioning the latter to act only on the needles with long butts during a course which follows at least one initial course and precedes a connecting course, and

control means for said additional sinker cam positioning the latter to act on all of the sinkers during said course which precedes the connecting course.

2. A circular knitting machine as in claim 1; wherein said needle lifting cam is movable between positions where it selectively engages only the long-butt needles and the butts of all of the needles, respectively, and

further comprising control means for said needle lifting cam moving the latter to said position where it engages only the long-butt needles during said course which precedes the connecting course.

3. A circular knitting machine as in claim 1;

wherein said butts of the needles are engageable from above with a profiled guide ring, and said means to effect slight lifting movement of the needles is constituted by a step on said guide ring engageable with all of the butts.

4. A circular knitting machine as in claim 1;

wherein said additional needle cam is also movable vertically to adjust the extent to which needles having their butts engaged by said additional needle cam are moved downwardly beyond said lowermost position to which the needles are moved by said withdrawing cam, and

further comprising control means for the vertical movements of said additional needle cam.

5. A circular knitting machine as in claim 4;

further comprising a control drum for regulating the operating cycle of the knitting machine, and wherein said control means for the vertical movements of the additional needle cam includes cams of different heights spaced circumferentially on said drum, and actuating means engageable by said cams of different heights in succession and correspondingly varying the vertical position of said additional needle cam.

6. A circular knitting machine as in claim 5;

wherein said cams of different heights are arranged on said control drum to move said additional needle cam to a lowermost position during the forming of the first initial course, to a highest position during the forming of a second initial course, to a central position during the forming of said course preceding the connecting course, and to a lower position, between said lowermost and central positions, during the forming of said connecting course.

7. A method of operating a circular knitting machine for the production of hosiery with a double, outwardly folded-over welt, which machine is equipped with sinkers each having an additional groove opening radially inward below the normal cast-off ledge thereof, said method comprising,

(A) during the forming of a course which follows at least one initial course and precedes a connecting course, the steps of lifting at least alternate needles sufficiently to cause the needles to engage thread fed thereto, slightly lifting each needle immediately following the normal downward withdrawing movement thereof, thereafter downwardly displacing the alternate needles to an extent beyond said normal downward withdrawing movement of the needles, and simultaneously effecting momentary radially outward displacement of all sinkers to an extent beyond the normal radially outward movement of the sinkers which accompanies said normal downward withdrawing movement of the needles so that the stitches of each initial course and of said course preceding the connecting course are retained in the additional grooves of the sinkers below the normal cast-off ledges; and (B) during the forming of the connecting course, the

steps of lifting each needle to engage thread fed thereto, slightly lifting each needle immediately following the normal downward withdrawing movement thereof, and thereafter downwardly displacing only alternate needles beyond the normal downward withdrawing movement of the needles while retaining the sinkers in radially inward positions so that said alternate needles which are downwardly displaced draw long loops of thread from the normal cast-off ledges of the sinkers to the stitches retained in said additional grooves with the thread for said long loops being supplied from the loose loops of thread on the slightly lifted needles between said alternate needles. 8. A method as in claim 7; further comprising varying the width of the stitches formed during successive courses by adjusting the extent of the downward displacement of the needles 7 following said slight lifting thereof so that a first initial course is formed with wide stitches, a second initial course is formed with narrower stitches, said course preceding the connecting course is formed with stitches of normal width and said connecting course is formed with still wider stitches to facilitate casting-off of the latter from the related needles.

References Cited by the Examiner UNITED STATES PATENTS 2,785,552 3/1957 Larkin 66-41 2,948,130 8/1960 McDonough 66-41 3,108,459 10/1963 Coile 66-57 X 3,116,620 1/1964 Hanel et a1 66-54 FOREIGN PATENTS 1,289,308 2/ 1962 France.

0 ROBERT R. MACKEY, Acting Primary Examiner.

MERVIN STEIN, Examiner.

P. C. FAW, W. C. REYNOLDS, Assistant Examiners.

Claims (1)

1. IN A CIRCULAR KNITTING MACHINE FOR THE PRODUCTION OF HOISERY WITH A DOUBLE, OUTWARDLY FOLDED-OVER WELT AND WHICH COMPRISES A ROTATED CYLINDER CARRYING A SET OF LATCH TYPE NEEDLES THAT ARE AXIALLY MOVABLE AND ALTERNATELY HAVE LONG AND SHORT BUTTS, RADIALLY MOVABLE SINKERS LOCATED BETWEEN THE NEEDLES AND EACH HAVING A CAST-OFF LEDGE AND AN ADDITIONAL RADIALLY OPENING GROOVE BELOW SAID LEDGE, A THREAD GUIDE FOR FEEDING THREAD TO THE SUCCESSIVE NEEDLES, A NEEDLE LIFTING CAM ENGAGEABLE WITH SAID BUTTS OF THE NEEDLES FOR RAISING THE LATTER TO A LEVEL AT WHICH THE NEEDLES CAN ENGAGE THREAD FED BY THE GUIDE, A NEEDLE WITHDRAWING CAM ACTING ON THE BUTTS OF THE NEEDLES FOR EFFECTING DOWNWARD MOVEMENT OF THE LATTER AFTER ENGAGEMENT OF THE NEEDLES WITH THE THREAD, A SINKER CAM RING CONTROLLING THE RADIAL MOVEMENTS OF THE SINKERS AND HAVING A PORTION EFFECTING RADIALLY OUTWARD MOVEMENT OF THE SUCCESSIVE SINKERS UPON SAID DOWNWARD MOVEMENT OF THE ADJACENT NEEDLES BY SAID WITHDRAWING CAM: THE COMBINATION OF AN ADDITIONAL NEEDLE CAM SPACED FROM THE LOWEST PART OF SAID WITHDRAWING CAM IN THE DIRECTION OF ROTATION OF SAID CYLINDER AND SELECTIVELY ENGAGEABLE WITH THE NEEDLE BUTTS TO EFFECT DOWNWARD MOVEMENT OF THE NEEDLES BEYOND THE LOWERMOST POSITION TO WHICH THE NEEDLES ARE MOVED BY SAID WITHDRAWING CAM, AN ADDITIONAL SINKER CAM SPACED FROM SAID PORTION OF THE SINKER CAM RING IN THE SAME DIRECTION, AND BY A CORRESPONDING DISTANCE AS SAID ADDITIONAL NEEDLE CAM WITH RESPECT TO SAID WITHDRAWING CAM, SAID ADDITIONAL SINKER CAM BEING SELECTIVELY ENGAGEABLE WITH THE SINKERS TO EFFECT RADIALLY OUTWARD MOVEMENT OF THE LATTER BEYOND THE MOVEMENT THEREOF BY SAID PORTION OF THE SINKER CAM RING,

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