US3460358A - Method of operating a double bed warp knitting machine - Google Patents

Description

Aug. 12, 1969 K. KOHL 0, 58

METHOD OF OPERATING A DOUBLE BED WARP KNITTING MACHINE Filed March 9, 1967 2 Sheets-Sheet l INVENTOR= KARL KoHL A q 9 MT" Aug. 12, 1969 KQHL 3,460,358

METHOD OF OPERATING A DOUBLE BED WARP KNITTING MACHINE Filed March 9, 1967 "2 Sheets-Sheet 2 INVENTOR KARL KOHL United States Patent Ofice 3,460,358 Patented Aug. 12, 1969 3,460,358 METHOD OF OPERATING A DOUBLE BED WARP KNITTING MACHINE Karl Kohl, Otfenbacher Landstr. 20, Hainstadt am Main, Germany Filed Mar. 9, 1967, Ser. No. 621,873 Claims priority, application Germany, Mar. 10, 1966, M 68,708 Int. Cl. D04b 23/02 US. C]. 66-87 1 Claim ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The invention relates to Raschel warp knitting machines, and particularly to a needle bar mechanism for a double needle bar Raschel machine, and to a method of operating the machine.

The two needle bars of Raschel warp knitting machines known heretofore move intermittently to shift the associated needles alternatingly between respective low and high positions in which the needles dwell during guide bar movements, the needles of one bar dwelling in the knocking ofi. position while the needles of the other bar are at maximum height.

This arrangement requires not only relatively long dwell times and rapid acceleration and deceleration of the needle bars, but also six changes in direction of movement for the guides during each knitting cycle (see Warp Knitting Technology by D. F. Paling, Columbine Press, Manchester, England, 1965, p. 218). The inertial energy absorbed by the guide and needle bar mechanisms during the reversals of movement is directly related to the wear of these mechanisms. The known needle bar mechanisms require relatively complex cams, and it is not possible to employ crank drives or their equivalents which can be built and maintained at relatively low cost.

SUMMARY OF THE INVENTION I have found that the shortcomings of the known needle mechanisms can be avoided and the number of guide bar movements reduced to a minimum by moving one needle bar from its low terminal position toward the high position while the other bar is still substantially in its terminal high position. More specifically, I move one needle bar from its low or knocking-off position to a position approximately equidistant from the low and high positions while the other bar remains nearer its terminal high position than the low position.

Such a mode of operation permits the use of a mechanism which cyclically and continuously moves each needle bar in such a manner that the vertical positions of the bars are substantially sinusoidal functions of time in the respective cycles. The cycles preferably are of equal duration and are offset in time.

It will be appreciated that the terms low, high," vertical and the like, as employed in this specification and the appended claim, relate merely to locations spaced along the normal needle path and to the direction of movement in that path which has at least a major vertical component in most warp knitting machines in practical use at this time. This invention, however, does not rely on gravity for operativeness, and the afore-mentioned terms are not to be construed to limit this invention to a specific orientation in the field of terrestrial gravity.

Other features and many of the attendant advantages of this invention will readily become apparent from the following description of a preferred needle bar mechanism when considered in connection with the appended drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 shows the needle bars and associated elements of a Raschel warp knitting machine of the invention in sectional side elevation;

FIG. 2 is the needle bar displacement diagram of a conventional Raschel warp knitting machine;

FIG. 3 is the needle bar displacement diagram of a Raschel warp knitting machine of the invention; and

FIG. 4 shows the needle bar mechanism of the invention in side elevational section.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows as much of a Raschel warp knitting machine of this invention as is needed for a discussion of the problem to be solved. Two parallel needle bars 1, 3 carry respective rows of latch needles 2, 4, only one needle of each row being Visible in the drawing. The needles are guided partly by stationary trick plates 1', 3' and move in respective longitudinal paths which extend mainly in a common vertical direction. This much is common to this invention and to conventional Raschel knitting machines.

Contrary to common practice, the needles 2 are in or closely adjacent their position of maximum height while the hooks of the needles 4 are above the associated trick plate 3', and approximately equidistant from the terminal high and low positions of their paths.

FIG. 2 diagrammatically shows the needle bar displacement of a conventional two-needle-bar Raschel warp knitting machine in the manner of the afore-cited book by Paling. The needles 2 and 4 of the known machine, which in themselves may be identical with the needles shown in FIG. 1, are moved upwardly from the lowermost positions only after the needles on the other needle bar have descended almost to their lowermost positions. The relative position of the needles 2, 4 shown in FIG. 1 cannot occur in a machine whose needle bar mechanism operates as shown in FIG. 2.

The needle bar displacement diagram of a machine of the invention, as shown in FIG. 3, consists of essentially sinusoidal curves, the ordinate of the diagram indicating the position of the needle bar or of the needles, and the abscissa indicating time or angular displacement of a rotary cam in the needle bar mechanism, as is conventional.

The cycles of needle bar oscillation are of equal duration and ofifset or one half of the duration of each cycle so that the needles 2 move upwardly in their path, as shown at 6 while the needles 4 are still substantially at their highest point at 5. The dwell of the needles and of the associated needle bars in their terminal positions is infinitely short, and the oscillating vertical needle bar movement is continuous. I have found that such needle movement is entirely consistent with normal knitting operations.

A mechanism of the invention suitable for providing the sinusoidal needle bar oscillations of FIG. 3 is illustrated in FIG. 4.

The needle bars 1, 3 carrying the needles 2, 4 are mounted on the free ends 7, 7a of respective guide arms 8, 8a whose other ends are pivotally supported on shafts 9, 9a. A connecting rod 10 of adjustable length hingedly links the arm 8 to a rocker arm 11 movably mounted on a shaft 12 and carrying two cam follower rollers 13 on its free end. The rollers respectively engage the outer and inner cylindrical faces of a circular cam rim 14 on a disc 16 which is rotated by an eccentric shaft 15, as indicated by the arrow 17. When the shaft 15 is rotated by the knitting machine drive to which it is connected in a conventional manner, not shown, the needles 2 move as described above with reference to FIG. 3.

The needles 4 are similarly moved by a connecting rod 10a hingedly attached to the arm 8a, a rocker arm 11a oscillating on a shaft 12a and carrying rollers 13a in engagement with the rim 14a of a cam disc 16a fastened to an eccentric shaft 15:: for rotation in the direction of the arrow 17a. The linkage which transmits motion from the shaft 15 to the needle bar 1 is a mirror image of that which transmits motion from the shaft 15a to the needle bar 3 in the illustrated position in which the needles 2, 4 are on the same level. It will be understood, however, that the needles move in opposite directions from the illustrated positions, the respective cycles being offset approximately 180 of cam position or one half of a cycle.

The simple sinusoidal motion of the needle bars 1, 3 is brought about by a mechanism whose reciprocating elements move only slowly and with small amplitude while the heavier elements 15, 16, 15a, 16a rotate continuously. It will be appreciated that the shafts 15, 15a are statically and dynamically balanced for the eccentricity of the discs 16, 16a in a conventional manner, not illustrated.

The Raschel knitting machine equipped with the needle bar mechanism of the invention is thus capable of higher operating speeds than an otherwise comparable conventional machine, its cams and other motion transmitting elements have a longer useful life, and they can be built at significantly lower cost.

It should be understood, of course, that the foregoing specification relates only to a preferred embodiment of the invention, and that numerous modifications and alterations may be made therein without departing from the spirit and scope of the invention set forth in the appended claim.

What is claimed is:

1. In a method of operating a Raschel knitting machine having two needle bars and means for oscillating the needle bars in respective paths between respective terminal high and low positions, the improvement which comprises moving one of said bars from said low position thereof toward the high position, while simultaneously moving the other bar from the high terminal position toward the low position, one of said bars being moved from the low terminal position thereof to a position equidistance from the terminal position of said one bar, the other bar being moved simultaneously from the high terminal position of the same to a position equidistance from the terminal positions of said other bar.

References Cited UNITED STATES PATENTS 1,796,579 3/1931 Rupf 66-87 XR 2,273,246 2/1942 Anderson 66-87 2,333,697 11/1943 Boaler et al. 66-86 3,171,271 3/1965 Noe 66-87 XR 3,221,520 12/1965 Bassist 66-87 FOREIGN PATENTS 892,689 3/1962 Great Britain.

RONALD FELDBAUM, Primary Examiner

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