US3457736A - Wing cam for pattern wheel knitting apparatus - Google Patents

Description

July 29, 1969 1.. MISHCON 3,457,735

WlNG CAM FOR PATTERN WHEEL KNITTING APPARATUS Filed May 13, 1968 INYEN'TOR. Lester Mlshcon BY 6 WITNESS: 957

M- MM j ATTORNEY United States Patent US. Cl. 66-50 3 Claims ABSTRACT OF THE DISCLOSURE A wing cam for use in a pattern wheel circular knitting machine is described as being radially positionable relative to the axis of a knitting machine, such wing cam being of a bilevel nature and being provided with a bladelike leading portion, and a narrower trailing part that cooperates with a stitch draw cam to define a needle butt raceway; the needle butt raceway permits the use of frictionless needles by such machine, with attendantly more efiicient power consumption and stitch construction, but principally such raceway obviates the droppedstitch problem common to pattern wheel knitting machines run at high speeds.

Cross reference to related applications Copending United States application Ser. No. 670,097, filed Sept. 25, 1967, of which the present application is a continuation-in-part.

Background of the invention Field of the inventi0iz.The invention relates to circular knitting machines equipped with pattern wheels, and in particular provides at a pattern wheel feed thereof an improved form of wing cam that is adapted for cooperation with the needles of such circular knitting machine subsequent to their being selectively raised by such pattern wheel.

Description of the prior art.In a circular knitting machine equipped witth pattern wheels, it is the usual practice, at each pattern wheel feed station thereof, to raise all needles to a predetermined height, and then to raise selectively, by means of the pattern wheel at such station, certain of those needles to tuck height; others to knit height; and those needles not raised to tuck or knit height are returned to welt height by means of a wing cam. Because of the possibility that the butts of improperly raised needles may collide with the leading edge of the wing cam, and therefore cause either the wing cam or such needles to break, it is customary to make such wing cam radially positionable out of cooperation with the machine needles, i.e., toward the axis of the machine, such wing cam being positionable against the tension of a spring. Since the wing cam is deflectable out of cooperation with the butts of the needles, it is usually adapted so that it can be easily repositioned for cooperation with the machine needles once the improperly raised needle, or needles, have passed. To this end, wing cams are generally blade-like in construction, whereby they may work themselves back into place by fitting between the butts of adjacent needles. United States Patent No. 2,006,821 shows a radially positionable wing cam of the type commonly found in pattern wheel knitting machines.

The use of a blade-like wing cam, while allowing returnafter-defiection, creates a problem that is not especially apparent in low speed knitting machines, but which is quite troublesome in modern high speed knitting machines. For needles which have been raised by a pattern wheel above the leading edge of a wing cam for cooperation with a stitch draw cam, operation of the machine in question at high speeds tends to cause rapid ricocheting of such needles, i.e., downward bouncing of such needles, as they collide with such stitch draw cam. Needle ricocheting, rather than the desired gradual guide of a needle down and along a stitch draw cam, caused dropped stitches in the fabric being knitted on the machine in question. This is because the needles, after being raised to the knit, or cast-off, level, say at a given feed station, are abruptly shot downward as a result of their collisions with the stitch draw cam of such feed station to a point which is well below the level at which yarn is to be drawn, whereby such needles miss the yarn being fed to them, and thereby drop their respective stitches without forming new loops therewith.

Aside from the matter of dropped stitches, the use of a prior art wing cam in a pattern wheel knitting machine necessitates the use by such knitting machine of friction needles, i.e., needles which are so sufficiently bent that once raised by a pattern wheel-they hold themselves in place within their respective needle slots. Were such friction needles not used in the prior art, selective needle positioning by the pattern wheel would become a meaningless operation, with such needles being free always to fall to their lowest points within their respective needle slots regardless of how they had been afiected by the pattern wheel. Also, the prior art use of friction needles in a pattern wheel knitting machine intrinsically means unfavorable power consumption, and the usual problems attendant thereto, to operate such machine, a matter which is not of minor importance when one realizes that there are several hundred needles in the ordinary circular knitting machine.

Summary of the invention To avoid the power consumption and needle positioning problems intrinsic to the use, in a prior art pattern wheel knitting machine, of friction needles, and to avoid the problem of dropped stitches when operating a prior art pattern wheel knitting machine at high speed, the present invention provides an improved wing cam that so constrains the butts of raised needle within and along a tightly controlled path that 1) such needles may be frictionless, and (2) ricocheting of the needles off a stitch draw cam at comparably high machine speeds is impossibledoing so in a way that preserves the self restoring quality that obtains with a blade-like wing cam. To this end, the present invention provides, for use in combination with the respective pattern wheel feed station of a circular knitting machine, a hybrid wing cam, the leading edge (in the direction of relative needle travel) of which is blade-like, and the trailing part of which constitutes a cushion cam adapted for cooperation with the stitch draw cam of the feed station in question to define a needle butt constraining path. In other words, to provide two heretofore antithetical cam functions, the wing cam of the invention is deliberately made of bilevel construction, being provided with a step between its leading and trailing parts, whereby a blade-like leading edge gets defined in such a way that assures an effective trailing cushion cam.

A principal object of the invention is to provide an improved wing cam for use in pattern wheel knitting apparatus.

Another object of the invention is to provide a radially positionable wing cam that is designed to provide positive needle control during stitch'setting for needles raised by means of a knitting machine pattern wheel.

Another object of the invention is to provide an improved pattern wheel section for a circular knitting ma- 3 chine, which section includes a radially positionable wing cam having a blade-like leading edge and a cushion cam trailing part, such trailing part being adapted so as not to prevent the radial re-positioning of such wing cam.

The invention will be described with reference to the figures, wherein:

FIGS. 1A and 1B are diagrams useful in describing the invention,

FIG. 2 is a perspective view of a knitting machine pattern Wheel cam section embodying a presently preferred wing cam according to the invention,

FIG. 3 is a sectional view illustrating the manner in which the wing cam of FIG. 2 is radially positionable, and

FIGS. 4A and 4B are views illustrating another embodiment of the invention.

While the invention is fully and clearly shown in FIGS. 1-4, additional views of the indicated cam section, showing in particular the adjustment means for the stitch drawn cam, may also be found in copendmg United States patent applications of Harry Agulneck Ser. No. 720,647, filed Apr. 11, 1968; the character reference numbers as herein employed are the same as those employed for corresponding parts in United States application Ser. No. 720,647.

With reference to FIG. 1A, a pair of friction knitting needles and 12 are shown about to engage respectively a wing cam 14 and a stitch draw cam 16. It can be assumed therefore that the needle 12 has been elevated, say by a pattern wheel, to a level L that is sufficient for such needle 12 to take yarn Y and set stitches in fabric at a point P. Similarly the needle 10 is assumed as not having been elevated by a pattern wheel, its butt 18 falling below the wing cam 14, and the needle 10 be1ng lower ed to welt height before it reaches a point where it begins to draw yarn Y. The wing cam 14, as is well known, is adapted to be radially deflectable against springtension (i.e., looking at FIG. 1A, in a direction which is into the page) so that in the event a needle is improperly raised, say by a pattern wheel, whereby the butt of the needle inadvertantly strikes the forward edge 20 of the wing cam 14, neither the wing cam nor the butt will break as the butt pushes the cam 14 out of the way Because of the deflectable nature of the wing cam 14, such wing cam is deliberately made blade-like. Were this not so, the w ng cam could not work itself back into place for cooperation with the butts of the needles. FIG. 1A illustrate that the wing cam 14 can fit between the butts of adjacent needles so that, once deflected out of cooperation with the needle butts, such butts will not forever keep the wing cam 14 from its normal position.

It is desirable that those needles which are raised, say by a pattern wheel, to remain so elevated and then be lowered along the length of the stitch draw cam 16, whereby they will draw yarn at the level L and set uniform stitches at the fabric line F. As the speed at which the knitting machine in question is driven increases, the tendency for the needles to strike and richochet off the stitch draw cam 16 becomes greater. Therefore, at some given machine speed, a raised needle will, for example the needle 12, strike the cam 16 and be shot straight downward to below the yarn feed level L, as shown in phantom, thus completely missing the yarn Y and causing dropped stitches.

Whereas it is well known to control needle butts within a tight raceway by means of a cushion cam set below a corresponding stitch draw cam, such as expedience, without further modification, would nullify the very function of the blade-like wing cam found to be so essential for cooperation with a knitting machine pattern Wheel.

Referring to FIG. 1B a hybrid wing cam according to the invention is provided: the leading edge 20' thereof being a blade-like cam that can work its way between adjacent needles just as easily as the cam 28 of FIG. 1A; the trailing edge 22 being a cushion cam of lesser radial thickness than the edge 20 (thereby to provide the bladeedge) but being of sufiicient radial width that the butt 23" may be constrained within the raceway defined by the surfaces 16, 22. Thus, the needle 23' may not only be of the frictionless type, but also the objectionable matter of needle ricocheting is avoided by means of the invention.

The pattern wheel section block 24 of FIGS. 2, 3 is similar to the section block shown and described in the abovenoted copending United States patent application Ser. No. 670,097, being however directed to an improved wing cam according to the invention.

The section block 24 rotatably mounts a pattern wheel 26 for selective elevation of needles according to the setout of jacks in the slots of the pattern wheel 26. The block 24 has a cam face member 32 secured to it by means of screws (not shown), the leading edge 36 of such face member 32 providing a raise cam for elevating needles to about tuck level. In this, the presently preferred embodiment of the invention, two butt needles are employed, the lower butt of each needle riding up the raise cam 36, and the upper butt of each needle being adapted to be selectively raised by the pattern wheel 26. A cam piece 38 is secured to the section block 24, and such cam piece 38 provides a cushion cam surface 40 that prevents inordinate amounts of needle flight. The block 24 is provided with an inclined face 44 against which a bracket 46 is secured, such bracket 46 together with the face 44 sandwiching a stitch draw cam 48 for sliding movement therebetween. The stitch draw cam 48 is urged upward by a spring 50 that is secured to the block 24 by a screw 52. A bell crank arrangement, disclosed more fully in copending United States application Ser. No. 720,647 includes an arm 54 that is adapted to push down upon the upper end of the stitch cam 48 against the tension of the spring 50. The crank 56 pivots on an axle 58 in response to adjustment of a knob 62. The cam face member 32 is provided with a cutout 64 in which the hub 66 of a wing cam arm 68 is pivotally supported on a pin 69. The cam face member 32 is further provided with an undercut 70 into which the wing cam arm 68 is adapted to reside (usually), the wing cam arm 68 being urged into such undercut 70 by a spring 72.

A bilevel wing cam 76 according to the invention sits atop the wing cam arm 68. The leading edge 78 of the cam 76, in the direction of relative needle travel, is blade-like; and the trailing part 80 of the cam 76, in combination with the cam surface 48, defines a needlebutt raceway 82, the trailing part 80 of the wing cam 76 being radially narrower than the leading edge 78 thereof, thus forming therebetween a step 84. The most forward part 88 of the leading edge 78 of the wing cam 76 is beveled in a radial direction so that in the event such edge is struck by the butt of a mispositioned needle, the wing cam 76 will be radially deflected, against the tension of the spring 72, out of the Way of the needle-butt and into a cutout 90 in the block 24.

FIG. 2 shows two needles in phantom, the needle 92 being assumed to have been raised first by the raise cam 36, and then by the pattern wheel 26. The butt of the needle 92, as such needle is carried along in the usual manner, enters the raceway 82 and is therein constrained, the needle 92 being prevented from ricocheting like the needle 12 of FIG. 1A, irrespective of the speed at which the machine in question is being operated. The other 94 of the two needles shown in phantom in FIG. 2 is assumed to have been raised by the raise cam 36, but is assumed to hvae not been elevated any further by a corresponding jack of the pattern Wheel 26. Thus, the butt of the needle 94 gets carried along in the usual manner to pass under the blade-like leading edge 78 of the cam 76, being carried thereby to welt level like the needle 10 of FIG. 1A. In the event the needle 94 is inadvertently partially elevated in response, say, to friction between the needle 94 and the walls that define the slots of the pattern wheel 26to a point wherein the lateral movement of the needle 94 causes its butt to strike the edge 88 of the wing cam 76, such wing cam will get depressed into its cutout 90. That is, as the misplaced butt rides up the beveled edge 88 of the wing cam 76, the butt causes the Wing cam arm 68 to pivot about its pin 69 (see FIG. 3), whereby the wing cam 76 is moved out of the way of such butt, and both the wing cam and the needle butt are thereby protected against breaking. Continued lateral movement of such misplaced butt ultimately causes it to drop into the raceway 82 and, as this occurs, the blade-like portion 78 of the Wing cam begins to work itself back into place between sub sequent adjacent needles in the manner indicated in FIG. 1A. Thus, it is seen that two heretofore incongruous cam functions are provided in a radially defiectable wing cam by providing such cam with a bilevel construction.

While the invention has been described in its preferred form, it is to be understood that the Words which have been used are words of description rather than of limitation, and that changes within the purview of the ap pended claims may be made without departing from the true scope and spirit of the invention. For example, see FIGS. 4A, 4B, it is within the scope of the invention to provide a wing cam wherein both the leading and trailing parts are blade-like, provided, of course, that the leading part 100 is radially wider than the trailing part 102, and provided that such trailing part 102 is adapted for operation with a stitch cam to define a needle-butt raceway.

Having thus set forth the nature of the invention what is claimed herein is:

1. In a pattern wheel feed station of a circular independent needle knitting machine having tandenly disposed, in the direction of relative needle travel, a raise cam (36) followed by a pattern wheel (26) followed in turn by a stitch cam (48), said pattern wheel (26) being adapted to raise selected ones of the needles (92), (94) raised by said raise cam (36) to predetermined knitting heights, the improvement comprising:

(a) compound cam means (76) disposed in the direction of relative needle travel between said pattern wheel (26) and said stitch cam (48),

(b) means for spring biasing said compound cam means (76) radially of said machine for cooperation with 40 said needles, (92), (94), said compound cam means (76) being provided with first (78) and second (80) parts,

(a) said first part (78) being in the form of the blade, being disposed before said second part (80) in the direction of relative needle travel, and being so provided with a larger radial dimension than said second part (80), that said first part (78) may be in contact with a given needle when said second part (80) is not, said first part (78) being adapted to intercept those needles which are not selectively raised by said pattern wheel (26) and to lower said nonselected needles, and (b) said second part (80) of said compound cam means (76) being adapted for cooperation with said stitch cam (48) to define a raceway (82) along which the butts of said needles (92), (94) are con strained to move. 2. A cam section for a circular knitting machine comprising:

(a) a raise cam (36) for cooperating with the needles of said machine, (b) a pattern wheel (26) disposed to cooperate selectively with certain of the needles (92), (94) raised by said raise cam (36), (c) a wing cam (76) adapted to lower those needles not selectively raised by said pattern Wheel (26), (d) means for spring biasing said wing cam (76) for engagemnet with the needles of said machine, (e) a stitch cam (48) adapted to lower those needles selectively raised by said pattern Wheel (26), characterized in that said wing cam (76) has first (78) and second (80) levels, the first being Wider than the second and being disposed before the second in the di rection of relative needle travel and operative to lower said needles not selectively raised, and said second level (80) being adapted for cooperation with said stitch cam (48) to define a raceway (82) for constraining the butts of said needles (92), (94).

3. The apparatus of claim 1 wherein said needles of said knitting machine are of the frictionless type.

References Cited UNITED STATES PATENTS 1,181,520 5/1916 Glenn 6638 1,925,450 9/1933 Levin.

1,970,238 8/ 1934 Kretser.

2,539,790 1/1951 Mishcon et al.

FOREIGN PATENTS 308,071 3/1929 Great Britain.

WM. CARTER REYNOLDS, Primary Examiner US. Cl. X.R. 6657

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