Patent Grant
10934642
This patent application is the national phase of PCT/EP2016/067904 filed Jul. 27, 2016, which claims the benefit of European Patent Application No. 15179084.7 filed Jul. 30, 2015.
Various types of knitting machines are well known. Circular knitting machines, flat knitting machines or warp knitting machines belong to the most important types of these machines.
Knitting machines usually comprise at least one needle bed for supporting knitting tools. Needle beds of circular knitting machines are often called “cylinder”. This phrase takes their cylindrical shape into account. In the present publication the impression “needle bed” refers to all kinds of devices that support knitting tools no matter if they are flat, cylindrical or whatever.
Knitting tools are for example needles, sinkers or the like. Knitting tools are parts of knitting machines that are directly involved in the loop forming process and hereby have contact to threads. The different knitting tools grasp, lead or hold down the threads. In the present publication all knitting tools are called “system components”.
One kind of special system components are slider needles. The publication DE 698 03 142 T2 shows a slider needle. The respective slider's profile is u-shaped in the plane perpendicular to the slider's movement. As a result the legs of the u-shaped sliders partially embrace the shank of the needle on which the respective slider is moved. One could also say that any leg is partially arranged between the needle shank of the needle on which the respective slider is moved and the adjacent needle or the adjacent needle shank. During the knitting process there are relative movements between the needle shank and the slider. Hereby the slider temporarily closes the opening for the thread inside the hook or carries the thread along the needle shank. In doing so the slider gets regularly in contact with the thread.
During knitting the various types of system components acting in different types of knitting machines have relative movements to at least one kind of needle bed. These relative movements in channels of the needle bed generate some problems which are inherent in most modern knitting machines:
High frictional load between system components and needle bed or even sticking of the system components in the channels. The friction causes wear on system components and needle bed and generates undesirable heat in the knitting machine.
In publication DE 10 2013 104 189 A1 the problem of sticking of sinkers in the channels caused by the not longitudinal components of the actuation of the sinkers' butt is discussed. This publication proposes to use two sinkers of different length in one common groove to solve that problem.
The publication EP 0 672 770 A1 shows a flat knitting machine for knitting a tubular knitted fabric. One of the shown knitting machines uses two needles in one common groove. The needles are provided with transfer elements as blades. The said publication mentions that a spacer can be necessary to prevent interference between the needles caused by the transfer elements. The spacer itself and its mode of operation are not described in more detail.
The publication DE 33 11 361 A1 shows a knitting machine comprising needles and sinkers for loop-forming that move in the same longitudinal direction. Said knitting machine comprises a first cylinder placed in a lower region of the knitting machine where the needles are supported in channels. The needles used have a very long shank so that the hook is always far outside the needle cylinder in an upward direction. On top of the needle cylinder there is an additional cylinder for supporting the sinkers and the sinkers are short compared to the needles. The aforementioned long shanks of the needles are on top of the trick walls of the channels of the cylinder for the sinkers and therefore between the sinkers. The means for loop-forming of the needles and the sinkers (hook, holding-down-edge and knock-over-edge) extend in a region of the knitting machine where loops are formed. Said region is located upside of the cylinder of the sinkers. The needles and the sinkers are hereby at least partially separately guided in channels and thus the friction is reduced compared to an arrangement where needles and sinkers are solely guided in common channels.
The application DE 197 40 985 A1 shows recesses on the flat sides of knitting needles or on the walls of channels of a needle bed. The recesses are only provided in certain regions of the side faces of the knitting needles and not on the full length of the side faces of the needles. As a result of these measures, the surface area of the contacting surfaces of the said elements of the knitting process is reduced. Thus the energy consumption and the heat generation in the machine are reduced.
The application EP1860219A1 shows knitting needles with a relatively thin shank. Some of the figures of this publication show in a cross-sectional view that the needles are arranged askew or diagonally in the needle grooves so that only a top corner and the opposing bottom corner of the needles' cross section touch the needle groove. The surface area of the contacting surfaces is once again reduced so that the energy consumption of the system decreases. The heat generation is thus also reduced.
The application WO2012055591A1 shows a knitting machine which was constructed for the following purposes: High gauge, low manufacturing costs and low energy consumption. The publication proposes to provide two needles per needle channel.
Application WO2013041380A1 shows a knitting machine with improved actuation cams for side by side needles as shown by the aforementioned WO2012055591A1. The knitting machines can be produced at lower costs and high quality fabrics can be produced.
The DE610511B discloses two very similar types of needles. Both types comprise a thick (in the direction of the width of the needles) and stable rear part which carries the needle butts. The difference between the two needle types is that the first group is provided with a longer rear part than the other type.
The front parts of both types of needles, which support the hook, are relatively thin. The front parts have the same length.
In the needle beds shown by this publication a segment of the thin front part of each of the needles is guided in a respective slot of the needle bed. Needles of the long type surround groups of needles of the short type. An end segment of the rear part of the long needles is additionally guided by respective slots. The side faces of segments of the thicker rear parts of adjacent needles are in contact with each other. The DE610511B aims at reducing the costs for grinding the common long needle channels of the needle beds of most knitting machines: These long channels are replaced by the above mentioned slots which only cover relatively small segments of the length of the needles. However, this publication fails to teach a knitting device which is apt to the requirements of modern knitting processes: If the knitting beds shown in the DE610511B were subject to modern knitting velocities the needles would be bent. Therefore the needles would become subject to undue wear or the needles would even stick in the respective slot.
It is the object of the present invention to provide a process and a device which use an easier to manufacture needle bed which is also fit for modern loop forming velocities.
The inventive loop forming process uses at least one movable spacer between the system components which are equipped with loop forming means and which are moved in the channels of the needle bed. The aforementioned use of the spacer allows the use of needle beds with very broad channels or grooves which can be equipped with a plurality of system components and at least one spacer. Very advantageous needle beds are equipped with channels which have a width which is equal to or more than 0.8, 0,9, 1, 1.2, 1.3, 1.5, 2 or 3 times the pitch of the respective needle bed. Most spacers are easy—and therefore cost effective—to produce.
In accordance with the inventive loop-forming process the system components are moved relatively to a needle bed. The direction of the movement of the system components with respect to the needle bed is the longitudinal direction defined by the longitudinal extension of the channels or grooves of the needle bed. The system components are inserted and moved in these channels. In an end region of the needle bed the loops are formed. As already mentioned the system components are provided with special means for loop forming such as hooks and latches. These means of the system components are moved in said end region of the needle bed (loop-forming zone). In said end region of the needle bed the hooks and latches of the needles have contact to the threads and form loops with said threads. Usually the spacers are placed away from the threads and do not contact them.
In accordance with the inventive loop-forming process at least one spacer is inserted in at least one channel of the needle bed. Preferably there is one spacer between two system components. It is also possible that there is more than one spacer between two system components or that there are also spacers between the system components and the walls of the channels of the needle bed.
The spacers define the distance between two adjacent system components. In a preferred embodiment the width of the spacers in a direction x, which is the direction of the width of the channels of the needle bed, is the same as the width of the walls which delimit the channels of the needle bed. Preferably, both side surfaces of the spacers, that are perpendicular to the direction x, are in mechanical contact to one of the side surfaces of each of the two adjacent system components.
The spacers can be shorter in the longitudinal direction than the system components. It is however advantageous if at least parts of the spacer extend in segments of the longitudinal extension y of the grooves in which the system components are provided with butts. The spacers have no means such as hooks or latches that are intended for contacting threads. The shape of the spacers allows them to define the distance of the system components even in the end region of the needle bed. The spacers do not get in contact with the threads.
The movement of the at least one spacer has the same longitudinal direction as the direction of the movement of the system components. In most cases, the spacer or even a plurality of spacers is put in one groove with a number of system components. It is also advantageous to place at least one spacer between a wall and a system component. The spacers are moved with respect to the needle bed (first relative velocity). One could also say that the at least one spacer of the present invention replaces a wall which delimits two grooves of a state-of-the-art needle bed of a knitting machine. The relative velocity between the spacer and the two adjacent system components can be much lower than the relative velocity between the wall of the state-of-the-art needle bed and the system components in the two grooves. Therefore, the friction between the system components and the spacer is lower than the friction between the system components and the aforementioned wall of the state-of-the-art needle bed.
This fact might be the source of another important property of the present invention: inventive embodiments and processes can save energy.
Most system components comprise two opposing flat side surfaces which can at least partially come in contact with walls of channels of the needle bed in which they are inserted for knitting. Additionally, parts of smaller surfaces can get in contact with the bottom of the channel. At least the first mentioned kind of friction can be reduced by the movable spacers.
A relative movement of the at least one spacer with regard to the two adjacent system components is advantageous. Most of the time, the movements of the spacer and the two adjacent system components comprise periodic movements between minima and maxima in the longitudinal direction of the needle channels. The phrase “there is a relative movement of the at least one spacer with regard to the two adjacent system components” does not exclude that there could also be periods of time during such a period of the movements in which these elements (the spacer and the two adjacent system components) rest with regard to each other.
It is advantageous, if the periodic movements of the spacer and one or both of the adjacent system components relative to the needle bed have the same direction at least during half of the period of the movement of the spacer. Longer periods of time in which the movements have the same direction are even more advantageous (more than 70, 80 or 90%).
Other tests (other needle types, other oil, other velocities, other gauges) have shown that it can be sufficient if the period of time in which the system components and the spacers are driven in the same direction is longer than the period of time in which these elements have opposed directions. The latter condition is different from the first condition since there are also periods of time in which the elements are nearly at a standstill with respect to each other.
If the relative movements of the aforementioned elements with regard to the needle bed is positive (more than nil) and have the same direction, the relative velocity between the spacer and the two adjacent system components is lower than the relative velocity of each of the aforementioned elements with regard to the needle bed. This fact seems to be important for the overall reduction of the energy consumption during the loop forming process. Therefore, more advanced inventive loop forming processes are characterized by very long periods of time in which the aforementioned condition is met.
In most knitting machines longitudinal relative movements between system components and the needle bed are initiated by relative movements of the needle bed to cams. These relative movements are in the direction x of the width of the channels and thus perpendicular to the longitudinal relative movements in the direction y. Thus the interaction of system components with the cams initiates the longitudinal movement needed for forming loops. However, this kind of interaction also delivers force in a perpendicular direction to the system components which pushes them against the walls of the channels and is therefore a source of undesired friction. As said before the force which moves the system components and spacers in their respective grooves can be provided by the relative movements of the spacers' and system components' butts along cam tracks which are defined by cams which are fixed on cam holders. Circular knitting machines are usually provided with cam holders which are fixed on the machine frame. Flat knitting machines often use cam holders which are part of carriages which are moved with regard to the needle bed. In both cases there is a relative movement between cam holders and needle beds.
The elements which are driven by the aforementioned relative movement between cam holders and needle beds could be provided with at least one butt.
The movements performed by the at least one spacer and the two adjacent system components relative to the needle bed could be equal (the same velocity and/or magnitude of movement etc.). The respective movements could however have a certain delay of time (a certain phase shift).
Such movements by spacers and system components can be initiated by the same at least one cam (even all cams necessary for the movements inside one system can be the same). In the latter case all aforementioned elements would follow the same cam track (all movements are the same but have a delay).
It is also advantageous, if at least one of the two adjacent system components provides the spacer with the force for its movements. Usually such a spacer doesn't need a butt for interacting with cams. The transfer of the respective force from the at least one system component to the spacer can for example be provided by the friction between these elements.
As already mentioned above the spacers are preferably devoid of loop forming means whereas the system components are provided with such means. Even more preferably, the spacers do not control the movement of such system components directly or indirectly via another element. This means that the spacers, according to the present publication do not preferably serve as controlling element or controlling sinker (for example for knocking over sinkers or the like). It is also advantageous if the spacers also do not serve as a means for selecting needles or system components during the knitting process (selection element, selection sinkers). It is therefore also preferred if the spacers are devoid of recesses, protrusions, juts or the like which guide a—or establish mechanical contact with a—system component or with a further member, which controls a system component.
The distance between the two adjacent system components is only or exclusively defined by one or by a plurality of spacers. If there is a plurality of spacers which defines the distance between the two adjacent system components, at least two spacers could have contact with one of those system components.
An adjacent system component is a system component which is nearest to the other adjacent system component in one direction in the same needle bed.
Further characteristics and advantages of the invention will become better apparent from the description of the figures. The figures show preferred but not exclusive embodiments of the invention and therefore provide non limiting examples. Most of the individual features shown can be used with advantages for improving the present invention in its broadest form.
The line 53 is a symmetry line which is directed in the longitudinal direction y parallel to the side surfaces of the needles' or system components' 11, 12 shanks 39 and which crosses the centre of the needles' hook 20. The distance between the two symmetry lines 53 shown in
The embodiment shown in
In the embodiment shown by
As already mentioned above the spacers 10 and system components 11, 12 can also use the same cams 18—or in summary—the same cam track as the spacers 10. In this case the butts of the aforementioned elements 10, 11, 12 can be provided at a corresponding longitudinal position on the different elements' longitudinal extension.
Moreover, the readers are reminded that the term “system components” is not limited to needles but also comprises sinkers and other devices which get in contact with the thread 23 and take part in the loop forming process.
The spacers 10 essentially move in the same direction as the system components 11, 12. The spacers are also devoid of loop forming means like hooks 20 and latches 24 and the like and do not take part in the loop-forming process. Moreover, the spacers essentially define the distance between two neighboring or adjacent system components 11, 12. Most of the time the sinkers 25 and the respective system components 11, 12 still have a certain distance, so that the distance between these system components 11, 12 is the sum of these distances and the sinkers' 25 width. These aforementioned distances in the loop forming area are necessary to provide the yarn with enough space for the loop forming process and to avoid too much friction between the different elements.
As said before
The figures elucidate a foremost property of the invention. The grooves 16 are broader (possess a bigger width in the direction x) than state-of-the-art needle beds 14. Needle beds which are appropriate for the present invention have a width which is bigger than their pitch times 0.7, or even bigger than their pitch 52, or even bigger than their pitch 52 times 1½, 2 or 3. The grooves 16 which are provided with the aforementioned pitch can have a length which equals 95, 90, 85, 80, 70 or 60% of the system components' length. The respective grooves 16 are easy to clean and the oil consumption of the overall new device is smaller than in the case of most comparable state-of-the-art devices.
In the case shown in
Such movements are advantageous for all embodiments of the invention. One beneficial way to transfer the force for the movements to the elements involved is to provide the elements 10, 11 and 12 with butts 17 and move the needle bed 14 with respect to cams 18 which transfer force to the butts. In the case shown in
The movements of the aforementioned elements 10, 11 and 12 can be in accordance with a harmonic function of time like sinus or cosinus.
The relative velocities VSN1 and VSN2 between the elements 10, 11, 12 are relatively low in comparison with the relative velocities between the elements 10, 11, 12 and the needle bed 14. As already mentioned before, this fact leads to a reduction of the friction between the elements 10, 11, 12 in comparison with a state-of-the-art needle bed which is provided with immovable walls 15 instead of a spacers 10. Therefore, inventive embodiments can save energy.
Surprisingly, tests have shown that such a shift of the movements of spacer 10 and adjacent system components 11, 12 has its advantages. The gist of this measure is to prevent neighbouring elements 10, 11, 12 from resting with regard to each other. Such a rest can for example take place in the period of time 6 in the case of movement shown in
This rest can necessitate a higher force in order to restart the respective relative movement of these elements (stick slip effect).
Therefore it is advantageous for all inventive embodiments, if the magnitude MN1B and/or MN2B of the extrema of the movement of at least one of the two adjacent needles with regard to the needle bed is lower than the magnitude MSN1 of the extrema of the relative movement of the spacer 10 with respect to the respective system component 11, 12.
As mentioned above
If the force for the movements shown in the first three figures is provided by cams, the delay 13 is simply the delay (time difference) with which two adjacent elements pass through the same cam.
If the force for the movements shown in
The butts 17 of the spacers 10 and the butts of the system components 11, 12 are driven through the passages 35 of different groups of cams 18. As a result the spacers 10 and the system components 11, 12 have different cam tracks. The “distance or phase difference” 5 is caused by the distance (preferably in x-direction) of the extrema 37 of the different passages 35 (see
The aforementioned way to drive the elements is really one advantageous way to provide force for the loop-forming process: Two different groups of cams 18 are provided per system. One group interacts with the butts 17 of the system components 11, 12 and another group interacts with the butts 17 of the at least one spacer 10.
As already mentioned before, the above described details of different movements can be performed with benefit by all inventive embodiments.
The spacer's 10 movement can be different from the movement performed by the needles 11, 12. “Different” means that there can be a shift between the extrema of the movements of the needles 11, 12 and spacer as already discussed above. But there are other possibilities: the spacer can perform a different movement which is to say it can perform movements which do not stop with regard to the other two elements 11, 12. Therefore the spacer can follow a cam track which is formed in a different way than the cam track of its adjacent system components 11, 12. Another possibility is to let the spacer start its relative acceleration with regard to the needle bed 14 at an earlier moment in time (or at another point in the second direction x) than the adjacent system components 11, 12. An earlier start of the spacer's acceleration is advantageous in this context for all embodiments.
In summary, the most advantageous measure in this context takes place in the phases 60. In these phases there is no relative acceleration of the two adjacent system components 11, 12 of one groove. In at least one of these phases the spacer 10 is provided with a relative acceleration with regard to the system components 11, 12.
In the first phase 60 shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 15179084 | Jul 2015 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/067904 | 7/7/2016 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2017/017138 | 2/2/2017 | WO | A |
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| Number | Date | Country | |
|---|---|---|---|
| 20190003088 A1 | Jan 2019 | US |
