US 2695506 A
Description (OCR text may contain errors)
NOV. 30, 1954 w, KQHLMANN 2,695,506
CIRCULAR KNITTING NEEDLE Filed April 1'7, 1951 z o Will/er $15 "I;
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BAIov-nz/ United States Patent 0 CIRCULAR KNITTING NEEDLE Walter Kohlmann, Altena, Germany, assignor to a firm Joli. Moritz Rump, Altena, Westphalia, Germany Application April 17, 1951, Serial No. 221,412
Claims priority, application Germany July 31, 1950 3 Claims. (Cl. 66-117) Circular knitting needles for ordinary use are provided with a flexible middle portion and thickened knitting ends. Needles the middle portion of which consists of a massive metal wire have proved a failure. It is more suitable to manufacture the middle portion of such needles of a wire rope the opposite ends of which are clamped into the knitting ends having the shape of small pipes. However, also such needles do not represent a perfect solution, as special measures are required for the purpose of preventing, as a result of the bending and breaking strains, the thin single wires from breaking shortly before the place where the wire rope is inserted into the tube-like knitting ends thereby causing a pinching of the thread when knitting.
According to the invention this disadvantage is removed in that the middle portion of the needle consists of a massive flexible thread of artificial material, e. g. a thermoplastic material such as nylon, a synthetic linear polyamide. Such thread of artificial material has the required toughness and elasticity to resist the special strains and stresses of such a needle.
According to a further feature of the invention the ends of the middle portion of artificial material are clamped in the tube-like thickened knitting ends in a similar way as the ends of the metallic wire rope used up to now. It has proved that the permanent bending and breaking strains at the endangered regions near the joints of the middle portion and the tube-like knitting ends do not cause a premature breaking or other deformation if artificial material of the mentioned kind is used for the middle portion.
It has already proved that the tube-like knitting ends of circular knitting needles provided with a middle portion consisting of a wire rope are strained in consequence of the permanent bending movement of the middle portion in such a degree that they spread or split at the joints causing the stitches to be caught during returnknitting. According to a former suggestion of the applicant this disadvantage can be removed if the wire rope is provided with a thickening of ball-like or ellipsoidal shape immediately before its entrance into the knitting ends said thickening being formed by spreading the wire rope e. g. by turning its windings rearwardly at this place, whereby simultaneously breaking of the wires of the rope at their joint with the tube-like knitting ends can be avoided. The cause of this efiect of the known needles is the fact that by loosening the connection of the wires the conditions of elasticity are changed suchwise that the bending plane is displaced rearwardly from the endangered cross section at the joint.
The invention relates to the further problem to utilize the described effect of thickening known in connection with metallic wire ropes for such circular knitting needles, in which, according to the invention, the middle portion consists of a strand of artificial material which does not allow to form a thickening or knot by spreading in a similar way as with the metallic wire rope. Furthermore, it has proved that-in consequence of the special quality of such thread of artificial material--the use of a ball-like or ellipsoidal thickening or knot does not result in the described rearward displacing of the bending plane and that, therefore, it is impossible with such shapes of knots to keep the bending and breaking strains off from the endangered cross section at the joints of the wire and the tube-like knitting ends.
According to a further feature of the invention such effect may be attained if the middle portion consisting of Patented Nov. 30, 1954 an artificial material is provided with a thickening or knot of a generally pear-like shape or the shape of a truncated cone produced by upsetting, said knot being firmly pressed with its broad base against the annular front face of the tube-like knitting end. The strong axial pressure exerted thereby in connection with the distribution or accumulation of material at the joints produced by the special shape of knot causes the desired rearward displacement of the bending plane. The arrangement according to the invention further prevents forming of small gaps at the joints by which the thread or fibres of the knitting wool may be caught so that the stitches are guided in an improved manner over the joints.
According to a further feature of the invention the knot may be of different shape as well as of different dimensions. In all cases it must be taken care that at the transitions from the circumference of the cone to the middle portion on the one hand and to the base of the cone on the other hand sharp edges or angles are avoided.
The largest diameter of the knot is chosen preferably of the same size as the outer diameter of the joining portion of the knitting end.
The tube-like knitting ends may consist of metal or of artificial material. In the latter case, according to the invention, the small pipes of artificial material serving as knitting ends should be provided with a metal insertion which may also be shaped like a small pipe at least in the rear region, the ends of which pipe pressed against the knot of the middle portion being advanced a little relatively to the end of the pipe of artificial material shaped to form a transition cone. The metal insertion used for such knitting ends not only gives the required strength to the highly strained knitting ends, but simultaneously creates the condition to produce a transition from the knitting ends to the middle portion of artificial material which transition is resistant against the strong strains. The metal insertion is advanced for a small measure (e. g. 0.5 mm.) with respect to the end of the tube of artificial material shaped so as to form a transition cone.
Tests have shown that it was impossible to use artificial material also for manufacturing the knitting ends of circular knitting needles for the reason that the required conical transition from the knitting ends having an enlarged diameter to the thinner middle portion weakens the wall thickness of the tube-like knitting ends consisting of artificial material in such a degree that in spite of the return displacement of the bending plane by the small knot provided at the end of the middle portion a deformation or splitting of the knitting ends arises at the joints. This disadvantage could not be removed even by forming the transitions from the knitting ends to the middle portion by thermoplastic welding of these portions of artificial material, a measurement which, by the way, is not possible without ado if difierent artificial materials are used for the middle portion and the knitting ends. The described disadvantages are removed, according to a further feature of the invention, if, the transition cone of the pipe consisting of artificial material and forming the knitting end is rearwardly displaced for a small amount relatively to the metal insertion thereby considerably relieving the sleeve of artificial material from the described strains. By the feature of the invention, therefore, the artificial material is only interrupted within a region of a very small length immediately before the two knots, which is also unobjectionable for knitting women suffering from rheumatism. Moreover, there is no objection to coat these metallic places, with a suitable cover for instance when using aluminium by eloxing.
The manufacture of a needle according to the invention is very simple. Preferably the metal insertion of the knitting ends is constituted along its whole length by a small pipe which is tightly inserted into a previously manufactured small tube of artificial material provided at its rear end with a transition cone. The end of the small pipe of artificial material projecting over the end of the insertion is then used to produce the massive pointed end of artificial material by thermoplastic deformation at the required temperature, the middle portion consisting of artifieial material being previously inserted into the rear end of ,theknitting end. During the. thermoplastic.deforma-..
tion the knitting end may be provided with edged surfaces in the region of the inserted middle portion by pressing. Ofcourse also round pressing may be chosen It suflices to insert the middle portion of artificial material 0.1 10415 mm.; of course, thisamount may also be in creased.
For the manufacture of knitting: ends artificial materials on. the basis of polyvinyl chlorideare especially suitable. Also other polymerisation products may be used, such as p lyv ny eide or- Po y t y en r mixed P l mer'isates, forinstance the copolymerof polyvinylchloride andamaleic acid ester, or further polycondensation products for instance on the basisof aminocaprolactarn;
The transition coneprovided according to the invention should be slender i. e. it should not havea too great angle so that the wall thickness of the pipe of artificial material is reduced gradually to zero, thereby at the same time facilitating the knitting process.
The drawing shows by way of example two embodiments of the.- invention,
Fig. 1 is a view. of a circularknitting needle, according to the invention.
Fig. 2 shows the joint of the middleportion and the knitting end in an enlarged scale;
Figs. 3-5 show another embodiment of the invention in which the knitting ends consistof artificial material.
Fig. 3 illustrates a knitting end and its connection with the flexible middle portion in an enlarged scale.
Fig.4 shows the connection between the middlle portiOldl and=the knitting end in a still further enlarged scale, an
Fig.5 shows the upper portion ofFig. 3 before the pointed end being formed.
' The circular knitting needle according to Figs. 1 and 2 consists-of the metal knitting ends 1 having the shape of small pipes and the middle portion 2 of a somewhat smaller diameter consisting of a flexible preferably polishedmassive strand of; artificial-material e, g. a. thermoplastic material such as nylon, a synthetic-linear polyamide. The strand 2 is provided a certain distance from its ends \Vith' massive knot-like thickenings, 3 having a longitudinal cross section of generally conical or pearlike shape produced by upsitting. The broad base 4 of i the knot 3abuts against the front'side of; the knitting end 1 vThe greatest. diameter of theknot is about equal to the outer diameter of the joining portionof the knitting end 1.. Of course the transitions from't e conical circumference t0 the base 4 and to the strandZ are rounded. The:outer. edge 5 of the front face of the knitting and opposite the knot is rounded but to a smaller degree, 6. g. it is taken 01h Fig. 2 shows in an exaggerated way by dot-and da h lines how the middle portion 2;is bent off.
While according to the embodiment shown in Figs. 1 and 2 the knitting ends consist of metal in Figs 3-5 another embodiment of the knitting ends is illustrated. Here, the. knitting ends consist of a small pipe 1b of artificial material into which a small metal pipe in is tightly inserted. Preferably polymerisation products such as polyvinyl chloride or polycondensation products such as aminocaprolactam are suitable for that purpose.
Theend of the small pipe 1b projecting over the metal pipe and a small rod 6 of artificial material inserted into the said projecting end, are thermoplastically pressed. so as. to form the pointed knitting end. At the rear end the small pipe vlb of artificial material is provided with a 2,695,506 Y r a transition cone 7 beyond which the metal pipe 1a projectsfor the small amount x (Fig. 4).
The middle portion 2 and the knot 3 are shaped in a similar way as describedwith respect to Figs. 1 and 2. The small metal pipe 1a may be made of any suitable metal such as steel, aluminium, brass, or the like. The middle portion and the knitting ends are connected with each other in a similar. way as when using metallic knitting ends, e. g. after the knot being jolted and the middle portion being inserted into the knitting ends, the knitting end is radially pressed onto the inserted middle portion 2 and simultaneously a strong axial pressure is exerted by the front face of the small metal pipe 1a against the base 4 of the knot.
Having thus particularly described the nature of my said invention and the manner in which the same is to be performed what I wish to have covered by Letters Patent is:
1. In a circular knitting needle a flexible inner member and two tubular rigid outer members, said inner member entering with its. ends into said tubular outer members, said inner member consisting of a tenacious strand of a polyamide material and extending short of the ends thereof and adjacent said outer members into frustoconical enlargements, the latter contacting the ends of the outer knitting members approximately with their largest cross-sectional area, tubular metal inserts in said outer members, ending short of said frusto-conical enlargements and tight-fittingly adjoining the contact faces of said frusto-conical enlargements.
2. In a circular knitting needle a flexible inner member and two tubular rigid outer members, the free ends of said inner member entering with its ends into said tubular outer members the latter having a larger diameter than said inner member, the latter consisting of a tenacious massive strand of a polyamide material the'ends of said inner member extending into the bores of said outer members, said inner member extending short of the ends thereof and adjacent said outer members into knot-shaped enlargements of which the diameter is substantially thersame as, the diameter of said outer members.
3. Ina circular knittingneedle a flexible inner member and two tubular rigid outer members, the free ends of said inner member entering with its. ends into said tubular outer members the latter having a larger diameter than said inner member, the latter consisting of a tenacious massive strand of a polyamide material, the ends of said inner member extending into the bores of said outer members, said inner member extending short of the ends thereof and adjacent. said outer members into knotshaped, enlargements having a frusto-conical shape and a step-shaped circular front face and contacting the outer knitting members with said step-shaped face.
References Citedin the file ofthis patent UNITED. STATES. PATENTS Number Name Date 1,286,125 Sessions Nov. 26, 1918 1,960,133 Aivazion May 22, 1934 2,183,791 Dunn Dec. 19, 1939 2,230,495 Kohlmann Feb. 4, 1941 2,561,522 Lobl July 24,1951 2,633,720 Robbins Apr. 7, 1953 FOREIGN PATENTS Number Country Date 173,618 Great Britain Ian. 6, 1922 392,667 Great Britain May 25, 1933