US2680959A - Warp guide construction for warp knitting machines - Google Patents

Description

June 15, 1954 R, w o 2,680,959

WARP GUIDE CONSTRUCTION FOR WARP KNITTING MACHINES Filed Feb. 16, 1955 Patented June 15, 1954 WARP GUIDECONSTRUCTION FOR WARP KNITTING MACHINES Richard L. Walford, Water-town, Conn.

Application February 16, 1953, Serial N 0. 336,992

7 Ciaims.

This invention relates generally to warp knitting machines, i. e., machines in which a large number of threads are knitted into a fabric, each thread running generally parallel to the length'of the fabric. More particularly, the invention relates to warp guides for attachment to warp knitting machine guide bars.

The warp guides of my invention may be used both in machines having latch needles and in machines having hook needles with independently moving tongues. My guide was conceived for use in. warp knitting machines in which, in contra-distinction to conventional practice, the guides do not, in any case pass between an adjacent pair of needles in a motion across the line of the needles. While machines of this class are not widely used, they are known in the art, and Celanese Corporation of Americas U. S. Patent No. 2,333,697 (Boaler et al.) of November 9, 1943, discloses one example of a machine having this characteristic. With such machines, the guides need not be formed in the conventional manner as a series of thin fingers, but may advantageously be of appreciable width at their operational ends, i. e. the ends which approach nearest the needles during the knitting operation.

As-is all too well known in the knitting art, the majority of faults in knit fabrics may be directly traced to the presence of waste (6:; g. frayed filaments, stripbacks, or slubs) in the yarn employed. At the present time, all multifilament yarns appear to have at least a small amount of waste associated therewith. If guides are used having eyes which offer appreciable resistance to the passage therethrough of Waste carried by Warp threads, waste will build up in the guide eye area, and thread breakages are apt tooccur.

The warp guide construction of my invention.

offers appreciably less resistance to the passage of waste through the crucial guide. eye area than the conventional guide constructions comprising a series of flat metal fingers having circular guide.

holes or eyes (usually formed by a stamping operation) at their operational ends. The operational ends or" my guides are appreciably Wider than thosev in use atpresent, leaving a comparatively narrow space between each adjacent pair of guides, so that there is only a short length of uncontrolled thread between theguides and needles. Furthermore, the warp guide construction of my invention lends itself to facile lacing up of the machine.

In its broadest aspect the new warp guide-construction may be defined as comprising a generally rectangular base plate and a plurality of similar thread guiding members disposed generally parallel to the major plane of said base plate and projecting outwardly from the leading edge of said base plate; said thread guiding members be-- ing-parallel'to, and equidistantly spaced from, one another; each of saidthread guiding members comprising a single length of resilient Wire air-- cuiarly bent through about 540 degrees at sub' stantially its mid-point to form acircular thread guiding loop-andtwo substantially parallel arms; theendsof the said arms remote from the loop being rigidly secured to said base plate; the loops of all the thread guiding means being equidistantly' disposed outwardly from the leading edge of said base platev The wire from which the guides are formed is preferably of circular crosssection. Wire of oval'cross-section could be employed without departing from the scope of the invention, but its use is not economically justifiable.-

Bending through about 540 degrees is mentioned in the statement of the invention in the preceding paragraph. It will be recognized that 540- isnot an arbitrarily selected figure, but is representative-of the amountof bending required to produce a one-and-a-half turn helix, and something approaching a-.one-and-a-half turn helix is obviously called for if the two arms of each thread guiding means are to be substantially parallel, as described in the statment of the invention. All the loops should be produced by. bendingin the same direction, i. e., they should all be right-hand helices or all left-hand helices. Actually I do not contemplate the use of left-hand helices since warp knitting machines areconventionally threaded (laced up) from right to left (as viewed by an operator in. front of the machine) and the provision of lefthand! helices would disturb. this. convention which, incidentally, has advantages.

In drawings illustrating embodiments of the invention:

Figure 1 is a perspective View of a portion of a guide; bar carrying two, warp guide constructions according. to the invention,

Figure 2-is a front view-of one of the warp guide constructions of Figure 1.

Figure 3 is a side view. ofv one of the warp guide constructions of Figure 1,

Figure 4 isa cross-sectional view showing, on an enlarged sc ale, one. of the thread guiding loops split through its middle and viewed along the line 4-4 in Figure 1,

Figures 5, Sand! are-sideviews of three different thread guiding members as they appear before they have been inserted in the base plate; Figure 5 showing a member having simple straight-ended arms; Figure 6 showing crimped arm ends; and Figure 7 showing outwardly bent arm ends.

Considering Figure 1 first, reference numeral It indicates a warp knitting machine guide bar carrying a number of warp guide constructions according to the invention, the constructions being generally indicatedby reference numerals l 1. Each construction ll comprises a generally rectangular base plate or block 12, whose leading edge is indicated at 13, and a plurality of similar thread guiding members 14. The members I l are fixed at one end within the base plate l2, are disposed generally parallel to the major plane of the plate, and. project outwardly from the leading edge 63 for equal distances. Members Hi are parallel to, and equidistantly spaced from, one another.

The base plate i2 is preferably formed from a soft metal having a low casting temperature, e. g., lead or a lead-base alloy; and the members I l may advantageously be secured to the base plate during casting of the latter. Certain thermoplastic materials and light metallic alloys are now commercially available which could reasonably be expected to be equally as effective in the formation of the base plate, as the metal mentioned as preferred in the preceding sentence; but I have not as yet conducted sufficient experimentation to be in position to recommend their employment. The base plate 12 is provided with a conventional alignment ridge I2A (see Figure 3) at its back, and a hole I23 (see Figure 2) whereby it may be secured to the bar by a screw lZC as shown in Figure 1.

Each thread guiding member 14 is formed from a single length of resilient wire of circular crosssection; and each length of wire is circularly bent through about 548 degrees at substantially its mid point to provide a circular thread guiding loop l5 (in the form of a one-and-a-half turn helix in which the half turn is in contact with the full turn throughout the length of the former) and two substantially parallel arms 16. The ends of the arms [5 are rigidly secured in the base plate i2. Where the rigid securement is obtained by embedding the ends of the arms in a metallic base plate l2 during casting of the plate, arms it having straight ends, as shown at ISA in Figure 5, may suffice, but crimped ends, as shown at 563 in Figure 6, or outwardly bent ends, as shown at MC in Figure '7, are preferred since the crimped or bent ends enhance the retention of the arms Within the metal of the base plate.

It may be noted in Figure 2 that, at the leading edge i3 of base plate l2, the lower arm I6 is directly below the upper arm; and it may also be seen that the lower and upper arms exhibit a divergency which increases with proximity to the loop l5. This divergence can, of course, be directly attributed to the fact that a portion of a one-and-a-half turn wire helix necessarily has a width which is at least twice the diameter of the wire. As a result of the divergence just described, the loops 15 are disposed at somewhat less than a right angle to the major plane of the base plate !2. This angular disposition of the loops has proved to be very advantageous when drawing in new warps since it facilitates the insertion through the appropriate loops of the thread-carrying arms of a dabber or similar 4 means employed for lacing warp knitting machines.

Of even greater importance, however, is the feature of minimum resistance to the passage of thread-borne waste through the loops l5; and the fact that the wire loop, being formed from wire of circular cross-section, offers little frictional resistance to the threads, whether they be virtually waste-free or not.

Referring to Figure 4, I wish to point out that the thread T will constantly be drawn against the loop in the area marked A, and will also be drawn against the loop on the opposite side (in the area marked B) during a portion of each knitting operation. Quite obviously the round Wire will offer less resistance to waste and establish less friction than the edges of the holes in conventional guides, which edges are substantially rightangular.

If, despite the minimized resistance, waste is caught in a loop I5 of a guide construction according to my invention, it will accumulate above wire turn 13, as indicated at D in Figure 4, and will be prevented, by wire turn C, from falling out of the left-hand side of the loop and being caught by needles disposed below the left-hand side of the loop. Waste will continue to accumulate at D until it tangles with the thread and is pulled out of the guide eye at the point marked B.

In order to give an idea of the diameter of wire which should be employed and the size of loop which should be made in the wire, I wish to provide the information that I have had excellent results with a 28-gauge machine in which I used guides according to the invention formed from wire of .010 inch diameter and having an internal loop diameter of approximately .057 inch. In the ZS-gauge machine the width of base plate l2 would be 1 inch and there would be twenty-eight members Hi. The width of the guide loops i5 is 0.020 inch which leaves an inter-loop thread passage space of about 0.015 inch, which space is ample for the passage of a denier knot.

What I claim as my invention is:

l. A warp guide construction for warp knitting machines comprising a generally rectangular base plate and a plurality of similar thread guiding members disposed generally parallel to the major plane of said base plate and projecting outwardly from the leading edge of said base plate; said thread guiding members being parallel to, and equidistantly spaced from, one another; each of said thread guiding members comprising a single length of resilient wire circularly bent through about 540 degrees at substantially its mid-point to form a circular thread guiding loop and two substantially parallel arms; the ends of the said arms remote from the loop being rigidly secured to said base plate; the loops of all the thread guiding members being equidistantly disposed outwardly from the leading edge of said base plate.

2. A warp guide construction as defined in claim 1, in which the said wire is of circular crosssection.

3. A warp guide construction as defined in claim 1, in which all the loops are bent in the same direction.

4. A warp guide construction as defined in claim 3, in which a line, drawn at the leading edgeof the base plate through the centre lines of both the arms of any selected thread guiding member, intersects the major plane of said base 7 plate substantially at right angles; and the loop of the selected guiding member, being of greater width than the remainder of said thread guiding member, necessarily assumes an attitude in which it is disposed at a small angle to said line; the angular disposition of the loops facilitating the passage therethrough of a thread dabber during the drawing in of new warps.

5. A warp guide construction as defined in claim 3, in which the base plate is metallic and the ends of the arms remote from the loops are embedded within the metal constituting said base plate.

6. A warp guide construction as defined in claim 5, in which the ends of said arms remote from the loops are crimped to enhance their retention in the metal of the base plate.

7. A warp guide construction as defined in claim 5, in which the ends of said arms remote from the loops are bent outwardly to enhance their retention in the metal of the base plate.

References Cited in the file of this patent FOREIGN PATENTS Number

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