US2977781A - Carrier tube - Google Patents

Description

This is a continuation-in-part of my application entitled Carrier Tube, Serial No. 717,366, which was filed February 25, 1958.

This invention relates to a yarn guiding element for use on knitting machines and more particularly to a carrier tube of the kind employed in seamless hosiery knitting machines.

The property of modern synthetic yarns, such as nylon, etc.,- to cause wear of yarn guides, particularly those made of steels, is widely recognized and has been the source of difficulties in the production of fabrics which should be knit with uniformyarn tension, as well as the cause of interruptions in production in order to renew worn guides which cause uneven tension in the yarn. Where possible,

yarn guides have been made, at least in part, from ceramic material, as the extreme hardness and smoothness of the ceramic better resists wear by the yarn. In the past, attempts have been made to fashion a carrier tube from ceramic, but have been generally unsuccessful due to the fact that the carrier tube is subjected to vibrations and strains in the knitting machine which cause a ceramic tube to fracture.

One of the principal purposes of the present invention is to provide an improved carrier tube which consists of a metal sleeve which receives annular ceramic inserts at either end, which are thus located in the area where the yarn passing through the tube principally contacts the tube.

A further object of the invention is to provide an improved carrier tube which contains ceramic inserts to take wear at the points or areas where the yarn principally contacts the tube, and which also comprises a steel support for the ceramic inserts which protect the ceramic and permit the tube to be fastened into the knitting machine and subjected to vibrations and shocks therein without fracturing the ceramic inserts.

A further object of the invention is to provide a carrier tube of the kind above described which is provided with a break-away tip, which permits the tip of the tube to break oif before it causes damage to the knitting head in the event the machine gets out of timing.

One form of the present invention is illustrated in the accompanying drawings and described in more detail hereinafter. I

In the drawings:

Figure l is a side elevational view of a carrier tube according to the present invention, also showing in dotted lines the central passage of the tube and the position of the ceramic inserts at either end;

Figure 2 is a longitudinal sectional View on the line 2-2 of Figure 1 of the same carrier tube;

Figure 3 is a top plan view of the carrier tube illustrated in Figure 1; t

Figure 4 is a side elevational view of a carrier tube according to the invention which is provided with a breakaway tip, a portion of the tube being broken away to show the construction of the tube end in section; and

States P m c Fatented AprQfI, 1961 Figure 5' is a similar view of another form of the tube with break-away tip.

Referring to Figure 1, it may be seen that the carrier tube, generally indicated by the numeral 10, comprises an elongated annular tube 12 which is preferably made of steel, although other rigid metals or-materials may be employed. The tube comprises a central passage 14 throughout the length of the tube, through which yarn is passed when the tube is assembled in known manner on a knitting machine. It may be seen from Figures 1 and 2 that the walls of the tube at the upper and lower ends are reduced in thickness to provide a shoulder 16, and consequently, to enlarge the diameter of the central passage 14 outwardly of the shoulders 16.

Referring to Figures 2 and 3, it may be seen that ceramic inserts 18 are set into these enlarged portions of the passageway with the bottoms of the inserts bearing against the shoulders 16. It will also be noted that the interior diameters of the inserts, when so placed, correspond to the interior diameter of the passageway which lies intermediate the shoulders 16, so that there is provided, after the inserts are placed, a passageway through the entire length of the tube which is of substantially uniform diameter. These inserts contact the yarn passing through the tube at the points where the yarn changes direction, and consequently at the points where the maximum wear occurs.

It is desirable in some instances to employ a filler, preferably an adhesive one, between the contacting surfaces of the inserts 16, or at least the sides thereof, and the tube12. This serves to provide a tight fit between the tube and the insert which is difiicult to achieve by making these elements with the exactness which would be required to prevent relative movement between them in the event such a filler was not employed. The use of the filler, if it is adhesive in-nature, also prevents accidental displacement of the inserts.

On occasions the timing of the movement of the yarn carrier with respect to the knitting head will become out of order and the tip of the carrier tube will strike the knitting head. It is desirable to have the tip of the carrier tube yield before the knitting head is damaged, and a carrier tube according to Figures 4 or 5 makes provision for this.

The tube shown in Figure 4 is similar to those earlier described except at the one end, at about midway of the length of the insert 18, the metallic tube 12 is provided with a circumferential score 20 which is of a depth nearly of the thickness of the wall of tube 12 at that point.

The tube shown in Figure 5 is constructed as described with reference to Figures 1-3, except that the shoulder 16 is formed inwardly from the end of the tube a distance equal to about one-half the length of the insert 18. Thereafter a metallic sleeve 22 is' positioned around the protruding end of the insert and secured thereon, preferably by adhesive filler. If desired a light solder connection to the tube 12 can be used to retain, or aid in retaining, the sleeve 22 in position. 7 A satisfactory ceramic for forming the insert according to this invention may consist of the type of ceramic material which is described in US. Patent No. 2,369,266 to Thurnauer, issued February 13, 1945. It is not necessary, however, that the ceramic havethe electrical proper ties therein described, although these may be desirable in some instances. Ceramics having properties satisfactory for the manufacture of inserts according to this invention may be identified by the following characteristics: Hardness, Mohs scale 8.9 Resistance to impact, charpy, pounds per square inch 2.4-6.3

Flexional strength, pounds per square inch 20,ooo-4o,oo0

Compressive strength, pounds per square AlSiMags, products of the American'Lava Corporation, are satisfactory ceramic materials. US. Patent No. 2,214,703 to Thurnauer describes ceramic materials satisfactory for the present invention.

It will be appreciated that the above characteristics are exemplary of the ceramic materials which may be employed, and that the invention may be embodied in various forms other than that illustrated and described specifically above.

Having thus described the invention, what is claimed as new is: I

1. A carrier tube for guiding yarn in a knitting machine comprising a rigid metallic cylindrical tube having a central passageway of circular cross section throughout the length of the tube, said passageway being enlarged at at least one end and of uniform diameter elsewhere along its length, a ceramic insert of annular form positioned in each such enlarged portion of said passageway with its central aperture concentric with said central passageway and being of the same diameter as said uniform diameter of said central passageway, the portion of said metallic tube which surrounds said insert being circumferentially cut whereby the tip portion of the tube will break away upon striking the knitting head of the machine on which the carrier tube is employed.

2. A carrier tube as claimed in claim 1 in which the enlargements of said passageway provide annular shoulders at right angles to the axis of said passageway which bear against the inner ends of said inserts,

3. A carrier tube as claimed in claim 1 in which a filler is placed between at least some of the contacting surfaces of an insert and said tube.

4. A carrier tube as claimed in claim 3 in which said filler is an adhesive.

5. A carrier tube for guiding yarn in a knitting machine comprising a rigid metallic cylindrical tube having a central passageway of circular cross section throughout the length of the tube, said passageway being enlarged at at least one end and of uniform diameter elsewhere along its length, a ceramic insert of annular form positioned in each such enlarged portion of said passageway with its central aperture concentric with said central passageway and being of the same diameter as said uniform diameter of said central passageway, the length of said ceramic insert being greater than the length of the enlarged portion of said passageway whereby said insert projects externally of said tube, and a metallic sleeve separate from said tube fitting around the external portion of said insert constituting a continuation of said tube whereby the projecting portion of the insert may break away under stress from the remainder thereof.

References Cited in the file of this patent UNITED STATES PATENTS 875,404 Barlow Dec. 31, 1907 1,070,036 Houghton Aug. 12, 1913 1,527,928 Scott Feb. 24, 1925 1,838,245 Amon Dec. 29, 1931 2,101,801 Weisbecker Dec. 7, 1937 2,126,249 Feustel Aug. 9, 1938 2,145,813 Kannegieter Ian. 31, 1939 2,214,712 Weisbecker Sept. 10, 1940 2,434,227 Rowe Jan. 6, 1948 2,453,513 Jauch Nov. 9, 1948 2,580,991 Barrett Ian. 1, 1952 2,756,482 Kaufmann July 31, 1956

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