DE2304727A1 - NEEDLE BASE PAD FOR KNITTING NEEDLES - Google Patents

Description

Patent attorneys
Dr. ing. Walter Ab'rtz
Dr. Dieter F. Morf
Dr. Hans-A. Browns
8Mflncten86. · »

3 ¹ January 1973 221 906

RAYCHEM CORPORATION

300 Constitution Drive, Menlo Park, Calif.,

V.St. A.

Needle foot covering for knitting needles

The invention relates to knitting needles as used in circular knitting machines and other knitting machines will. One end of these needles is shaped into a hook with which a pivotable tongue cooperates. A shaft part extends from the hook and a foot protrudes from the shaft. In every knitting machine there is one Larger number of such needles are used and for setting and moving the needles are of various types Needle holding and guiding elements required. The axial position of a needle is determined by its attachment of the needle butt in a needle butt guide slot, which can consist of a groove in the inner surface

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of a cylinder is cut. The cylinder rotates relative to the needle holder in which the needle is received, the needle must be in the axial direction move in a predetermined manner due to the cam action, that of the needle foot guide slot on the one in it Exercises needle foot.

To increase production on a knitting machine, If possible, the working speeds are increased, which leads to an increase in the speed of the axial reciprocation of the knitting needles leads. An increase in the speed of movement of the knitting needle and the consequent increasing vibration loads increase the risk of breakage, especially in the hook part the needle.

Various methods have already been used to reduce the risk of needle breakage, so that a higher one Working speed becomes permissible. One attempt is to make some bends in the needle shaft, to a certain degree of springiness between the To bring about the needle butt and the hook. Another attempt provides for the needle butt with a plastic cover to provide. For this purpose nylon 6,6 was provided; it was possible to increase the axial speed of the knitting needles without increasing the destructive vibrations, however, these covers had only a limited life, so increasing the knitting speed was not necessary meant real progress.

According to the invention, a needle with a belap; intended, the at least part of the base of the knitting machine needles covered, the material from which

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the pavement has both a relatively high shear modulus (i.e. over 10 pounds per square inch or 7.0.10 kg / cm lying shear modulus) as well as relatively good damping properties (i.e. a loss tangent over 0.01). Usually, most materials that have a high shear modulus poor damping properties, and materials with good damping properties have a low shear modulus. In the context of the invention, however, materials are listed which have the required combination of properties exhibit. The covering can be made of either a metal or a metal-polymer laminate or composite exist. The metals that have the desired damping properties include certain alloys of titanium and nickel and certain copper alloys, including copper-manganese alloys; particularly suitable alloys are discussed below.

The shear modulus is equal to the ratio of the shear force and the associated shear stress. It is expressed as Force per unit area, for example in pounds per square inch. The shear modulus can be used for layered materials to be determined. A laminate made of a layer of metal and a layer of a special polymer of the same strength has a shear modulus, the amount of which is about half the shear modulus of the one used Metal. That is, the strength of the laminate depends almost entirely on the metal layer.

The ability of a material to have a damping function exercise is generally expressed by its loss tangent, which is defined as

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1 V loss tangent = -ττ- In -τ

wherein:

A = amplitude of the η-th wave

A ^ = amplitude of the (n-l) th wave.

The specified amplitudes are determined at a low frequency using a torsion pendulum. Same as the The shear modulus can be the loss tangent of a layer material by testing a layer sample to be determined. The loss tangent of a laminate with an elastic layer and a viscous one Layer is essentially determined by the type of viscous material.

While the cushioning properties of nylon 6,6 are satisfactory (loss tangent = 0.026), its shear modulus is 0.14 · 10 · ⁶ psi or 9.8 · 10 kg / cm ² . In contrast, steel, as it is used in numerous needles, has a sufficiently high shear modulus g 4-2

(8.7.10 psi or 6.09.10 kg / cm) but not sufficient Damping properties (loss tangent = 0.0019).

The lining should also have good wear resistance, so that it is through the movement in the needle foot guide is not worn out. Metals that have the required shear modulus and matching loss tangent in addition to Have useful wear properties belong to a group that includes many alloys that also shows the peculiarity referred to as "memory", i.e. the return to the original shape when the temperature changes.

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A particularly effective composition includes alloys with titanium and nickel as the main components. It is known that many alloys with predominant proportions of titanium and nickel (for example the alloys according to US Pat. No. 3 17H 851 - WJ Buehler) have the ability to change from a martensitic crystal structure with excellent damping properties to an austenitic structure when heated . In the martensite state, these alloys have excellent damping properties. For this reason, the invention provides for the use of alloys with predominant proportions of titanium and nickel, the alloys being in the martensite state at the operating temperature of the metal parts. The possibilities for influencing the level of the transformation temperature are known; one can, for example, change the percentage of titanium and nickel. Furthermore, the transition temperature can be influenced by adding small amounts of other metals, for example cobalt, iron, aluminum and manganese. Details of the nature of such alloys can be found in a United States patent application dated July 2, 1970 (Ser.No. 51 809 - John D. Harrison, et al.), And in application Ser.No. 51 112 Harrison, et al. of the same day, also in Belgian patents 755 271 and 769 t68. An alloy that can be used in the context of the present invention consists (in atomic percent) of 50% titanium and 50% nickel. This alloy has a loss tangent of 0.036 and a shear modulus of 2.87.10 pounds per square inch (2.01 · ⁴ kg / cm ² ).

Generally speaking, metals that have their own

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Shank of the regression can be imparted by heating, good damping properties, if this Metals are in their low temperature state. Beta copper alloys (e.g. the alloys according to Belgian patent 758 862) are within the scope of the present invention usable.

If the covering is a metal-polymer composite, the metal itself does not need to be Having particularly good damping properties, rather its wear and friction properties play a role the crucial role. For example, hardened steel would be used as the metal and nylon 6,6 or as the polymer a polyurethane into consideration. Further details of these metal-polymer composites are provided below.

The polymer used in this composition should be excellent Have damping properties, and the following polymers therefore come into consideration, among others: Polyurethane elastomers, nylon such as nylon 6,6, tetrafluoroethylene copolymers such as FEP and PFA Polyimide, the repeating units of which have a tetravalent organic component and the remainder either 1,12-diaminododecamethylene or 1,13-diaminotridekamethylene (for example, according to US Pat. No. 3,551,200). The polymer should be at operating temperature the structural integrity of the floor covering.

Hardened steel and titanium-nickel alloys are used as the metallic component of such laminates austenitic crystal structure or other metals with relatively high strength and turkey

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Wear properties in consideration. Alloy stainless steel can also be used.

It is believed that a metal-Polyir.er facing is because of this able to give protection against breakage because it is able to use mechanical energy in the form of thermal energy submit. The heat is produced by the physical deformation of a density of a viscoelastic Material generated that is forcibly enclosed between the vibrating component and a thin metal layer is. Without wanting to be tied to a theory, it can be assumed that the needle breakage is caused by vibrational resonance and such vibrations are caused by the presence of the metal-polymer composite material reduced or prevented.

Accordingly, it can be assumed that the oscillation resonance is reduced or prevented in the same way if the covering is made of a metal that meets the requirements Has damping properties. When the needle butt makes the transition from a horizontal part to a Reached the inclined portion of the needle butt slot, the energy or "shock" should come from the metal-coated Damping coating is absorbed and therefore not transferred through the needle shaft to the hook part of the needle. The choice of a special material for the execution of the covering thus depends on the needle size and the oscillation frequency, and a given structure a covering will not be the most suitable under all operating conditions.

The coverings are conveniently "C" -shaped, you can but also choose a different shape. For example, the covering can be given the shape of an elongated "0". Of the

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Coating only needed to surround the upper and lower sides of the needle butt and could therefore take the form of a double ¹¹ U ¹¹ . The outside of the composite part is expediently rounded in order to reduce wear both on the composite part and on the needle butt guide. Various types of coatings can be applied to the outside of the lining in order to reduce corrosion, friction or wear. Such coatings are known to the person skilled in the art; they are therefore not to be described in detail here. Chrome plating (trade name "Electrolized") is given as an example.

The polymer can be attached to the needle butt in any conventional manner, for example by coating a pressed part over the needle butt before applying the metal part. You can also use the polymer directly Press on the needle butt and a hole or a number of openings or incisions can be made on the Provide a needle foot as a holder for the polymer. Besides that the needle butt can also be dipped into a liquid plastic, which is then hardened or dried and thus serves as a polymer part. In addition, metal and polymer can happen to each other must be glued before they are pulled onto the needle butt. Finally, polymer or metal, provided one can give them the property of recoverability by heating, in the form of a heat-shrinkable Tube must be placed over the needle butt before the metal part is placed around the polymer. It recommends aimed to create a close fit between the needle butt and the polymer to reduce impact from the needle butt could be applied to the polymer.

The external dimensions of the needle joint should of course

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can be modified so that the covering is placed over the foot can be without the lining can jam in the needle slot. On the other hand, the game should be between the outside of the pad and the needle slot should not be so large that a shock or impact between the pad and the slit can occur. Since this play can be increased by wear, it is wear-resistant Outside, made of tungsten carbide, for example, is practical.

The invention will now be based on exemplary embodiments are explained, which are reproduced in the accompanying drawings.

1 shows a side view of a knitting needle as it is used in knitting machines;

Fig. 2 is a side view of a needle butt slot with two needles inserted therein;

Fig. 3 shows the needle butt from the direction 3-3 (Fig.l) on a larger scale;

FIG. H is a view of the needle butt of FIG. 3 of FIG in front, partly from an inventive Surround covering;

Fig. 5 is a view from direction 5-5 in Fig. M-;

Fig. 6 shows a front view of a needle air and a second form of one constructed according to the invention Covering;

Fig. 7 shows a front view of a needle foot and

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a third forir. one constructed according to the invention Topping.

Fig. 8 shows a front view of a needle air and a fourth form of one constructed in accordance with the invention Topping.

According to the drawings, in particular according to FIG. 1, a knitting needle as used in knitting machines finds, generally designated 10. The needle 10 has a hook 11 at one end and one in the rest longitudinal shaft 12 which extends from the hook bar down to the base 13. From a A foot IH emerges on the side of the shaft 12. Relaxation notches 15 and 16 are provided in the shaft adjacent to the foot 14.

At the hook end of the needle 10 is a pivotably hinged tongue 17 which opens when the needle is moved up through a tissue, and which closes when the needle is brought back down will. Needles with such tongues are known per se and details of the mode of action are for the Understanding of the invention is unnecessary.

Fig. 2 shows a guide 21, the needle movement controls, and for clarity, two needles 10 and 20 that play in a needle slot 22 of the needle guide 21, Usually there is a large number of such needles on the guide. The needles are generally received in an associated series of (not shown) needle beds in a needle holder, which

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moved relative to the needle guide 21. The needle beds keep needles at a fixed mutual distance, allow but a movement in the longitudinal direction for them. The needle guide 21 can be relative to the needles in the move in the direction indicated by the arrow a. The needle butt, for example that designated 14 in FIG The needle butt of each needle, moves in the needle slot '22 and the displacement of the needle guide 21 relative to the needle can result in longitudinal movement of the needle. For example, if the guide 21 in Is moved in the direction of the arrow a, the needle 10 is pushed upwards in the direction of the arrow b until how the needle butt in the inclined section 23 of the needle slots s 22 is guided. When the needle foot reaches the horizontal section 24 of the needle slot 22, the vertical position of the needle remains so long unchanged until the needle butt reaches the inclined section 25 of the slot 22. Remains in a corresponding manner the vertical position of the needle remains unchanged when the butt of the needle is in the horizontal section 26 of the Slot 22 is located and the needle moves down when the foot is in section 27 of the slot runs. The inclination of the inclined sections of the needle slot 22 can also have a different amount than that shown Have 45 °.

The required faster movement of the needle guide has a higher relative surface velocity between the needle foot guide 21 and the needle result and one has found that the needle begins to break in the hook area if the needle movement is too fast.

The needle butt 14 of the needle 10 is shown in FIG. The relief notches 15 and 16 are used to reduce

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the stress used and reduce the risk of breakage at the transition point between needle butt and Needle shaft.

The risk of a needle breakage can be reduced by using a coating that is in contact with the needle foot guide. Such a coating is shown in FIGS. 4 and 5, according to which a C-shaped coating 30 partially surrounds ^{the needle butt I 1 *.} The lining 30 is made of a metal that has the required combination of a shear modulus greater than 10 pounds per square inch with a loss tangent greater than 0.01.

A covering useful for the purposes of the invention can also be made using a metal-polymer composite getting produced. Such a composite is shown in Fig. 6 shown, according to which a C-shaped coating partially surrounds the needle butt IH. The topping consists of one Metal part 35, and polymer compositions 36 and 37 are between the upper and lower surfaces of the needle butt 14 and the Arranged inside of the metal part 35. In such an embodiment, the metal part 35 does not need to be made of one Metal with good damping properties. The wear and friction properties of the metal can make the difference under these circumstances.

Another way of applying the polymer in a composite pavement is shown in FIG Metal part 40 is separated from the foot 14 by a C-shaped layer 41 made of a polymer. This arrangement of the polymer prevents any frictional contact between the metal part 40 and the foot 14 and leads to an improvement in the damping ratios of the composite.

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The composite arrangement according to FIG. 8 corresponds to that according to FIG. 7. According to FIG. 8, a metal part 42 is separated from the foot It by a C-shaped layer U 3 of a polymer. The upward and downward facing surfaces 44 and 45 of the metal part 4 2 are coated with tungsten carbide or another hard compound in order to improve the wear properties of the component 42. The tungsten carbide can be applied by flame plating if the metal part cannot easily be plated in another way. The component 42 can be made from those metals indicated as being useful in making the part. To further reduce wear, molybdenum disulphide or other friction-reducing substances or layers can be applied to the outside of the metal parts.

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Claims (1)

P ate nt claims Knitting needle for knitting machines, with a foot, characterized in that the foot (IU) is at least is partially covered by a covering, the work of which M- 2 substance has a shear modulus greater than 7.0.10 lg / cm and a loss tangent greater than 0.01, 2. Knitting needle according to claim 1, characterized in that a metal is used as the covering material. 3. Knitting needle according to claim 3, characterized in that the metal has the property of heat recovery can be imparted and that the temperature of the metal is below the heat recovery temperature. Knitting needle according to Claim 2, characterized in that an alloy is selected as the metal which essentially composed of titanium and nickel and the martensitic and austenitic states can assume and that the initial transformation temperature of the alloy is such that the alloy in operation of the machine, remains in the martensitic state. 309834 / 08U 5. Knitting needle according to claim 1, characterized in that that the covering material consists of a laminate r.it an outer layer made of metal and an inner layer made of polymer. 6. Knitting needle according to claim 5, characterized in that nylon 6,6 is provided as the polymer. 7 .. Knitting needle according to claim 5, characterized in that a polyurethane is provided as the polymer. 8. Knitting needle according to claim 5, characterized in that a polyimide whose repeating units of 1,12-diaminododecane or 1,13-diaminotridekan and are derived from a tetravalent acid fraction, is provided as a polymer. 9. Knitting needle according to claim 8, characterized in that the polyimide is 1,12-dodecamethylene pyromellitimide is provided. 10. Knitting needle according to one of claims 5 to 9, characterized in that at least part of the outer Metal surface is hardened. 11. Knitting needle according to claim 10, characterized in that the material causing hardness is chromium or Wolfrair.- 309834/0814 - 15 - carbide (H ¹ +, 4-5) is provided. 12. Knitting needle according to one of claims 5 to 11 »; characterized in that steel is provided as the metal. 13 «Knitting needle according to one of claims 1 to 12 * characterized» that the covering C30, 35 » HO ₉ , 4; 2) of the foot Cl ¹ O has the shape of an ⁿ C ^w . 14 · .. Knitting needle according to claim 13 »characterized» that the C-shaped covering consists of two ^w U ^w parts »with an upper end of one TJ ¹ * connected to the one upper end of the other" U ^w "while the other upper end of each "U" remains free. 15. Knitting needle according to one of claims 1 to 12 »characterized» that the covering has the shape of an elongated ⁿ 0 ^w or two "U ¹ *". 16. Covering for the foot. a knitting needle for use on knitting needles according to one of claims 1 to 15. 3QSS34 £ Q814