This patent application is the national phase of PCT/EP2015/055987 filed Mar. 20, 2015, which claims the benefit of European Patent Application No. 14163453.5 filed Apr. 3, 2014.
The invention relates to a knitting tool for a flat bed knitting machine or circular knitting machine comprising at least one needle bed having guiding grooves in which such knitting tools are movably guided.
Publication DE 197 40 985 C2 discloses punched knitting tools, in particular latch needles, that are adapted to be moved back and forth in longitudinal direction in guiding grooves of corresponding needle beds. These knitting tools comprise a shaft configured as a meander-shaped strip that defines a first height and extends away from the foot. The thickness of this shaft is reduced at some points. Extending from the shaft, there is a straight shaft extension that has, on its end remote from the shaft, a stitch-forming part that is configured, for example, as a hook and an immovably supported latch. In doing so, the stitch-forming part is that part of the knitting tool that is needed for the formation of stitches. The straight shaft extension has a second height that is lower than the first height of the shaft. The shaft extension has a uniform height. It is only the transition between the shaft and the shaft extension that is still configured with reduced thickness.
Such knitting tools have proven themselves to be excellent in practical applications because they allow faster knitting speeds.
There exist numerous additional suggestions for providing knitting tools with locations of reduced thickness. For example, German Patent 680 319 discloses a knitting tool with a laterally flexible shaft that is adjoined by a non-thickness-reduced shaft extension. During the knitting operation, the shaft is driven out of its guiding groove so that the thickness-reduced region of the shaft may act as a laterally flexible leaf spring. For a stitch transfer, the laterally flexible needle can be resiliently bent by a control member in order to come into contact with another needle.
As opposed to this, German Patent 20 63 724 discloses a needle, in which case the shaft displays reduced thickness in the region of the needle foot. This is to allow an elastic deformation of the shaft in order avoid a jamming of the shaft when it impacts the needle foot on a tappet part.
Publication DE 36 12 316 A1 discloses another embodiment of a needle with partially reduced thickness. In that case, the flanks of the shaft of the needle are provided with flat grooves extending in longitudinal direction. The shaft may be configured as a meander-shaped strip. A shaft extension extends from said shaft, said extension transitioning into a stitch-forming structure at its end. The shaft extension displays non-reduced thickness of the shaft.
Furthermore, publication DE 199 39 929 A1 shows a needle having a shaft that is provided, along its entire length, with dimples or extensions that form a concave or convex pattern. A knitting tool having a convoluted shaft is also known from this publication.
Considering all the aforementioned needles, the knitting speed of the knitting machine also increases the power necessary for driving the needles, as well as increases the machine temperature.
It is the object of the invention to decrease the need of power required by the knitting tools, as well as decrease the operating temperature of the knitting machine.
The knitting tool in accordance with the invention comprises a shaft from which extends at least one foot, in which case the shaft has a first height and a first thickness that is reduced at some points. The height should be measured perpendicular to the tool movement direction and perpendicular to the needle back. The thickness should be measured transversely thereto, i.e., perpendicular to the lateral flat sides of the knitting tool. Preferably, but not absolutely necessarily, the area of the thickness-reduced sections of the shaft exceeds the area of the non-thickness-reduced sections of the shaft. From this viewpoint, the area of the shaft extending beyond the foot remains without consideration.
Extending from the shaft there is a straight shaft extension that transitions on its end remote from the shaft in a stitch-forming structure that belongs to the stitch-forming part of the needle. In the case of a latch needle, the stitch-forming structure consists of a hook and a latch. Considering the longitudinal direction of the shaft, the stitch-forming structure ends at the tip of the latch being in its back position. In a compound needle, the stitch-forming structure consists of the hook and the part of the shaft located between the hook and the slide when the slide is in its maximum retracted position. The shaft extension defines a second height that is smaller than the first height of the shaft. This height is defined by the maximum height that is to be measured on the shaft extension. It could be measured on a bump or—if there is no bump on the shaft extension—be defined by the uniform height of the shaft extension, for example.
In addition, the shaft extension has at least two sections displaying different thicknesses. The section of the shaft extension having the smaller thickness is at least as long as the stitch-forming structure. The section of the shaft extension having the smaller thickness may have—at one or more points—a non-reduced thickness in order to form support locations. In other words: The shaft may comprise several locations of reduced thickness that are produced by grinding off material, for example. For thickness reduction, it is possible to provide one or more recesses on one flank or on both flanks, symmetrically or asymmetrically with respect to a longitudinal center plane of the knitting tool.
It applies to the shaft as well as to the shaft extension that the transition between the non-reduced thickness and the reduced thickness may be step-like, ramp-like, rounded or configured in another manner. The boundary between the non-reduced thickness and the reduced thickness may be in a straight line or in a curved line, e.g., arcuate. The boundary may also be arranged between sections of non-reduced thickness and reduced thickness at a right angle with respect to the needle back, inclined thereto or also parallel thereto. Different boundaries may be oriented differently.
Due to the thickness reduction on the shaft extension it is possible to minimize the friction between the shaft extension and the guiding channel of the knitting tool. There is given a certain mobility of the shaft extension transversely to its longitudinal direction, however this mobility does not interfere with the knitting process. Due to the reduced-contact surfaces between the knitting tool and the guiding groove, heat development and needed driving power are reduced. In particular, however, the thickness reduction on the shaft extension prevents too much of a change of the mobility resistance of the knitting tool during its back and forth movement in the guiding groove, as could otherwise occur during a change of the size of the contact surface between the knitting tool and the guiding groove.
The section of the shaft extension having the smaller thickness is arranged directly adjacent the remaining shaft and extends away from said shaft toward the stitch-forming part, in which case the shaft extension again exhibits the originally non-reduced thickness on the stitch-forming part. In this manner, it is possible to combine a gentle thread treatment with the easy mobility of the knitting tool having large sections of reduced thickness.
The section of the shaft extension having the greater thickness is preferably arranged directly adjacent the stitch-forming structure. In this manner, the knitting tool is imparted with high stiffness and lateral stability at the stitch-forming structure.
Preferably, the greater thickness of the shaft extension corresponds to the remaining, non-reduced thickness of the shaft. For example, the knitting tool may be a punched knitting tool of flat material, for example sheet metal, having uniform thickness.
Preferably, the sections having reduced thickness have been produced by cutting or grinding machining processes such as, for example, grinding or embossing, in that the said machining methods are used to impart the lateral surfaces of the shaft and the shaft extension with appropriate recesses. Preferably, the recesses are relatively shallow, wherein the depth of the recesses is within the range of 0.005 mm to 0.05 mm, preferably within the range of 0.01 mm to 0.03 mm. In a preferred embodiment, the depth of the recesses is 0.02 mm. Preferably, the recesses have a flat bottom—apart from their trailing zones—so that the cross-sections of the shaft extension in the thickness-reduced region have straight lateral edges. In doing so, the cross-section is preferably a rectangular cross-section (with rounded corners).
Preferably, the knitting tools in accordance with the invention have the said shallow recesses on both lateral flanks of the shaft extension and preferably also on the flanks of the remaining shaft, so that they can be used in right-rotating machines as well as in left-rotating machines. Furthermore, it is possible in this manner to produce knitting tools displaying particularly minimal straightness deviations. Furthermore, the knitting tools in accordance with the invention are suitable for use in flat bed knitting machines.
Preferably, the shaft of the knitting tool is configured as a meander-shaped strip shaft. To do so, said shaft has strips oriented in longitudinal direction and connecting strips oriented transversely thereto, in which case the strips and connecting strips define a meander shape. The strips and connecting strips may subtend, acute, right or obtuse angles. The angles may be defined uniformly or they may have different sizes. Large sections of the meander-shaped strip shaft preferably have a reduced thickness. However, in the foot region, the thickness is preferably non-reduced. Preferably, at least one other location of non-reduced thickness is provided on the shaft; preferably, two such locations are provided. If a second location of non-reduced thickness is missing on the shaft, it is possible to provide such a location on the shaft extension.
The recesses provided on the shaft of the knitting tool and on the shaft extension preferably have a uniform depth. As a result of this, the reduced thickness of the shaft corresponds to the smaller thickness of the shaft extension. In particular if the shaft has a meander shape, the needle displays a constant lateral resilient flexibility along its length, thus promoting high-speed applications.
Preferably, the knitting tool is a latch needle with a hook and a movably supported latch. However, the aforementioned concept may also be employed with other knitting tools.
Details of the invention and embodiments thereof result from the description and the dependent claims, and the drawings. They show in:
d the cross-section of the knitting tool according to
The knitting tool 10 has a shaft 15 from which extends an elongated shaft extension 16, e.g., in the form of a straight extension. The shaft extension 16 may be straight or otherwise elongated, e.g., slightly curved. As shown by
The shaft extension 16 is also connected to a longitudinal strip 20 via a straight connecting strip 23, the latter being oriented at a right angle relative to the shaft extension 16 and the longitudinal strip 20. The longitudinal strips 17, 18, 19 define a first height H1 as the maximum shaft height. Additional embodiments may have additional shaft regions displaying a smaller height H3 (see, e.g.,
The shaft extension 16 extending away from the shaft 15 preferably has a straight lower edge 26 that preferably is in one line with the lower edge as well as the foot section 24 and also additional sections, for example, the longitudinal strip 18, as well as a rear end section 27 of the shaft 15.
The shaft extension 16 has a maximum height H2 that is smaller than the height H1 of the shaft 15. In
On its end remote from the shaft 15, the shaft extension 16 transitions into a stitch-forming structure 28 that is adapted for stitch formation. The stitch-forming structure 28 comprises a hook 29 positioned at the end. Optionally, additional elements may be added such as, for example, a latch 31 that is pivotally supported by a latch bearing 30. In the present exemplary embodiment, its tip—when it is in its back position—marks the end of the stitch-forming structure 28.
The shaft extension 16 represents the connection between the shaft 15 and the stitch-forming structure 28. Said extension—extending from the shaft 15—has a first portion 32 that is shown dark in
Preferably, the shaft 15 also has several sections with different thicknesses. All such thickness-reduced regions are depicted dark in
The recesses 35, 36 can again be seen in
In accordance with the invention the portion 32 has a length that is greater than the length of the stitch-forming structure 28. Preferably, the length of the portion 32 is also greater than the length of the non-thickness-reduced portion 33. In many embodiments the length of the portion 32 is greater than the sum of the lengths of the stitch-forming structure 28 and the portion 33.
Furthermore, the length of the portion 32 of the shaft extension 16 is greater than the length of the thickness-reduced section of the longitudinal strip 20 that adjoins the shaft extension 16 in the direction of the foot 25 (via the connecting strip 23).
Preferably, the portion 32 is also longer than the thickness-reduced region of the longitudinal strip 17 adjoining the foot region 24, said longitudinal strip 17 contacting the side of the foot section 24 facing away from the shaft extension 16.
The shaft 15 preferably has three regions that are not thickness-reduced. In the knitting tool according to
The inventive knitting tool 10 may replace and operate like conventional knitting tools, without modification of the knitting machine. However, the knitting tool has been optimized in view of the required driving power and its temperature behavior. In symmetrical embodiments in accordance with
The minimization of the lateral contact between the knitting tool 10, in particular in the region of the shaft extension 16 and the lateral surfaces 13, 14 of the needle bed 12 promotes easy operation of the knitting tool, without compromising the knitting precision. Inasmuch as the recesses 35, 36 do not extend over the entire shaft extension 16 but only in the portion 32 thereof, as well as in select locations of the shaft 15 and in between, there are locations with non-reduced thickness D, D2, such as, for example, in portion 33 as well as the connecting strips 22, 23 and the foot section 24, there are defined support and contact points that position and guide the knitting tool 10 in a precise manner. The length between the individual support locations may be configured consistent with the required application. Regarding this, reference is made to the embodiments of the knitting tool 10 as illustrated by
The knitting tools 10 shown in
As is shown by
In the needle according to
Considering the shaft extension 16, again each and every configuration as in
Different therefrom, only individual connecting strips 22c, 22b or also others are non-thickness-reduced in the embodiments according to
For single-path machines, the knitting tools according to
Further modifications are possible. Regarding this,
A further instructive example of a knitting tool according to the invention is shown by
The inventive concept explained initially in general and then with reference to various exemplary embodiments in particular, can be implemented not only with latch needles of the most diverse types but also on other knitting tools, e.g., compound needles.
A knitting tool 10, in particular a latch needle, intended for a high-speed knitting machine has a meander-shaped shaft with thickness-reduced regions. Adjoining the meander-shaped shaft is a straight shaft extension 16 that also has a thickness-reduced portion 32. Due to its height H2 that is smaller than the height H1 of the shaft 15, the shaft extension 16 is separated from the shaft 15. The thickness-reduced region 32 of the shaft extension 16 has a length that is at least clearly greater than the length of the stitch-forming structure 28 carried by the shaft extension 16. Preferably, the thickness-reduced region 32 is overall longer than the non-thickness-reduced region of the shaft extension 16. This configuration provides a surprisingly powerful knitting tool 10 suitable for high operating speeds.
Number | Date | Country | Kind |
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14163453 | Apr 2014 | EP | regional |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2015/055987 | 3/20/2015 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2015/150123 | 10/8/2015 | WO | A |
Number | Name | Date | Kind |
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3949572 | Kopal | Apr 1976 | A |
4036036 | Ashmead | Jul 1977 | A |
4255948 | Sanders | Mar 1981 | A |
4625527 | Fukuhara | Dec 1986 | A |
4681150 | Fukuhara | Jul 1987 | A |
5901582 | Hennig | May 1999 | A |
6122938 | Henning | Sep 2000 | A |
6298692 | Kuroda | Oct 2001 | B1 |
6860121 | Jurgens | Mar 2005 | B2 |
6892556 | Landenberger | May 2005 | B2 |
7874183 | Fehrenbacher | Jan 2011 | B2 |
Number | Date | Country |
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680319 | Aug 1939 | DE |
2063724 | Jul 1971 | DE |
3612316 | Oct 1986 | DE |
19604954 | Feb 1997 | DE |
19740985 | Apr 1999 | DE |
19939929 | Apr 2000 | DE |
1333568 | Oct 1973 | GB |
Entry |
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International Search Report and written opinion in corresponding International Application No. PCT/EP2015/055987, dated May 28, 2015, 4 pages. |
Office action in corresponding Bangladeshi Application No. 102/2015/843, dated Jul. 3, 2016, 2 pages. |
European search report in corresponding European Application No. 14163453, dated May 28, 2014, 3 pages. |
European office action in corresponding European Application No. 14163453, dated Apr. 11, 2016, 3 pages. |
Number | Date | Country | |
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20170029990 A1 | Feb 2017 | US |