Needle loom having delayed weft insertion

Abstract

The aim of the invention is to allow, in a loom comprising a weft thread insertion device (40) having a weft needle (42) and a weft shaft lever (44), which are operatively connected to the main shaft (45) of the loom by means of the crank drive (13), for a delayed entry into the shed and an early exit therefrom. This aim is achieved in that a toggle lever system (46) is arranged between the crank drive (13) and the weft shaft lever (44), and in that the weft thread insertion device (40) having the weft needle (42) continues to be driven by the weft shaft (47) via a second lever system.

Description

[0001] Needle loom with delayed weft insertion

[0002] Technical area

[0003] The invention relates to a needle weaving machine, in particular a needle ribbon weaving machine, with delayed weft insertion and applications therefor.

[0004] State of the art

[0005] In needle-band looms, the drive of the weft needle movement has long been a problem discussed in the prior art. For example, CH 633 331 assumes that the weft needle drive is connected to the main drive shaft of the loom via a crank and lever system. Such a weft needle drive is shown schematically in Fig. 2. Figure 4 schematically shows the geometry of the weft needle movement, and Figure 4a shows the course of the weft needle movement with a shed entry at approximately 85°.

[0006] As proposed in WO 94 / 26964 A1 and WO 2012 / 163571 A2, needle ribbon looms can also have multiple, interchangeable weft threads – preferably with weft threads of different colors, but also with weft threads of different materials or thicknesses – which can then be exchanged by changing the weft thread, in the case of WO 2012 / 163571 A2 using a heald frame. WO 2017 / 042015 A1 presents a weaving machine in which knitting or laying threads are incorporated. WO 2017 / 2161 17 A2 dispenses with the mechanical connection between the main shaft of the needle ribbon loom and the weft thread insertion, and proposes implementing the weft thread movement using a linear actuator or a rotary actuator.However, all of these applications share the problem that the weft insertion needle should not enter the shed too early, either to simply have a wider open shed or to allow more time to ensure the weft thread change or the insertion of the knitting or covering threads safely and smoothly. The simplest way to achieve this goal would be to simply have the weft needle initially travel a certain distance outside the shed. However, this would have the major disadvantage of requiring unnecessary long travel distances and also disadvantageous accelerations, which must be avoided, especially at high weaving speeds.

[0007] Description of the invention

[0008] The object of the invention is to propose a needle weaving machine, in particular a needle ribbon weaving machine, in which the weft needle insertion into the shed can take place late without having to accept the disadvantages mentioned above.

[0009] The object of the invention is achieved by a machine according to claim 1. The measures of the invention have the primary consequence that, with such a weft needle drive, in which a toggle lever system is arranged between the crank drive and the weft shaft lever, the movement of the weft shaft is distorted. The weft needles, driven by the weft shaft via a second lever system, are modified in their movement by the effect of the toggle lever in such a way that they enter the shed with a delay or exit it prematurely. In addition, they perform a small return stroke when they are outside the shed. This results in the following advantages - in accordance with the above-mentioned task, namely:

[0010] Advantage 1 : Larger compartment opening:

[0011] With the weft needle drive, this is often the case. In the current state of the art, the shed opening where the weft needle enters the shed is still very small. In comparison, the shed opening with the weft needle drive according to the present invention is already approximately twice as large. This increases the security against under- or over-stacking warp threads, which tend to cling or stick together due to electrostatic charging. The weaving process becomes more reliable, and the resulting fabric exhibits far fewer weaving defects.

[0012] Advantage 2: Smaller weft needle radius: With a conventional weft needle drive, the reed has only moved very slightly from the reed beat-up point by the time the weft needle enters the shed. However, the measures of the invention mean that the reed has already moved significantly further from the reed beat-up point by the time the weft needle enters the shed. This results in a further advantage: the weft needle radius can be selected smaller without the weft needle colliding with the reed during its movement through the shed. A smaller weft needle radius allows for a more compact design of the weaving station, and the mechanical load on the weft needle drive is reduced (smaller mass to be accelerated).

[0013] Advantage 3: Simple, reliable weft thread change

[0014] The weft needle drive according to the present invention is also advantageous in a machine with weft thread change: As described in WO2012 / 163571, the weft threads to be inserted into the weft needle, which is equipped with a fork, are brought into the insertion or removal position by the movement of selected shafts. However, with the weft needle drive according to the prior art, it is not possible to use the normal shaft change times for this purpose. Instead, the shaft change time must be selected earlier for removal and later for insertion. This is unproblematic with electronically controlled shafts. However, with mechanically operated shafts, special eccentrics or chain links are required, and setting up the machine is correspondingly complicated.Since much more time is available for changing the weft threads with the weft needle drive according to the present invention, and since the weft needle performs a small return stroke as described above, it is possible to utilize the normal shaft change times for the weft thread change. This greatly simplifies machine setup and makes the weft thread change process more reliable.

[0015] Advantage 4: More reliable insertion of the guide needles on a machine with the incorporation of knitted threads.

[0016] The delayed entry of the weft needle into the shed is also very advantageous on a machine equipped with a device for incorporating knitted threads. With this device, at least one guide needle piercer pierces the open shed from above when needed and brings at least one knitted or effect thread into the lower shed in such a way that it is pierced over by the weft needle and thus incorporated into the fabric. The guide needle piercer has little time for the piercing movement (typically around a 90 degree machine angle) because it can only begin this after the reed beat-up and must already be sufficiently deep in the lower shed before crossing with the weft needle. The delayed weft needle insertion increases the available time by approximately 25%, which allows the guide needle piercer to penetrate deeper and thus create a larger and more reliable knitted thread shed.

[0017] The above-mentioned elements, as well as those claimed and described in the following embodiments, to be used according to the invention are not subject to any special exceptional conditions in their size, shape, use of materials and technical conception, so that the selection criteria known in the respective field of application can be applied without restriction.

[0018] Short description of the drawings

[0019] Examples of the weaving machine are described in more detail below using the drawings, which show:

[0020] Figure 1 shows a weaving machine (perspective) with a knee lever joint according to an embodiment of the invention,

[0021] Figure 2 shows a weaving machine (perspective) with a weft needle drive according to the state of the art,

[0022] Figure 3 shows the geometric conditions of the movement of the weft needle, according to the embodiment of the present invention according to Figure 1, Figure 3a shows the movement of the weft needle tip with a shed entry at approximately 110° machine angle, according to the embodiment of the present invention according to Figures 1 and 3,

[0023] Figure 4 shows the geometric conditions of the movement of the weft needle, according to the state of the art according to Figure 2,

[0024] Figure 4a shows the movement of the weft needle tip with a shed entry at approximately 85° machine angle, according to the state of the art according to Figures 2 and 4,

[0025] Figure 5 is a plan view of the weaving site at the time when the

[0026] Weft needle enters the shed, according to an embodiment of the present invention according to Figures 1 and 3,

[0027] Figure 5a is a side view of the open shed according to Figure 5 (embodiment of the present invention),

[0028] Figure 6 is a plan view of the weaving site at the time when the

[0029] Weft needle enters the shed, according to the state of the art according to Figures 2 and 4,

[0030] Figure 6a a side view into the open shed according to Figure 6 (state of the art),

[0031] Figure 7 shows the schematic structure according to an embodiment of the present invention with shafts for changing the shot color,

[0032] Figure 8a shows the movements of the weft needle according to an embodiment of the present invention according to Figure 1 and Figure ?, Figure 8b shows the movements of the weft thread control shafts according to an embodiment of the present invention according to Figure 1 and Figure 7,

[0033] Figures 9a to 9i show the process of changing the weft thread according to the embodiment of Figure 7,

[0034] Figure 10a the movements of the weft needle according to the state of the

[0035] Technique according to Figure 2 and Figure 7,

[0036] Figure 10b the movements of the weft thread control shafts according to the

[0037] State of the art according to Figure 2 and Figure 7,

[0038] Figures 11a to 11i show the process of weft thread change according to the state of the art,

[0039] Figure 12 shows the position of the needle piercer at the time of the blade stop according to another embodiment of the present invention,

[0040] Figure 13 shows the reliable piercing of the guide needle at the time of weft needle entry into the shed according to the embodiment of Figure 12.

[0041] Ways to implement the invention

[0042] Figure 1 shows an embodiment of the invention, namely a weaving machine with the reed 10, the drive motor 12, the main shaft 45 driving a crank drive 13, a warp thread feed 14, and a shedding device 16 suitable for forming a shed 18. The shed 18 comprises the weaving station 15 for producing the fabric 20, in which a weft thread 24 is inserted by means of a weft needle insertion device 40 having a weft needle 42. The weft needle 42 is driven by the weft shaft lever 44, which is connected to the main shaft 45 or the crank drive 13 by means of the toggle lever system 46. The inventive embodiment according to the present embodiment differs from a weaving machine according to the prior art cited here according to Figure 2, in particular by the connection of the weft needle drive to the main shaft 45 by means of the toggle lever system 46.

[0043] While the movement of the weft needle 42 in the prior art design is approximately sinusoidal—as shown in Figures 4 and 4a—the movement of the weft needle 42 driven by the modified drive system with the toggle lever 46 is modified by the action of the toggle lever 46 in such a way that it enters the shed with a delay and exits it prematurely—as shown in Figures 3 and 3a. In addition, it performs a small return stroke when it is outside the shed 18.

[0044] Fig. 5 and 5a and Fig. 6 and 6a each show a plan view of the weaving point and a side view of the open shed at the time when the weft needle enters the shed. In the weft drive according to the prior art, the shed opening h at the point where the weft needle enters the shed 18 is still very small, as can be seen from Figs. 6 and 6a. In comparison, the shed opening h in the weft drive according to the embodiment of the invention is already approximately twice as large, as can be seen in Figs. 5 and 5a. This increases the security against under- or over-stitching of warp threads, which tend to cling or which can stick to one another due to electrostatic charging. The weaving process becomes more reliable and the fabric produced has far fewer weaving defects. Also shown in Fig.6 shows that, with a conventional weft needle drive, the reed 10 has only moved very slightly from the reed beat-up point at the time the weft needle enters the shed (dimension a in Fig. 6). Fig. 5 shows that the reed 10 has already moved significantly further from the reed beat-up point at the time the weft needle enters the shed. This results in the further advantage that the weft needle radius R can be selected to be smaller without the weft needle 42 colliding with the weaving reed 10 during its movement through the shed 18. With a smaller weft needle radius R, a more compact design of the weaving station is possible, and the mechanical load on the weft needle drive is reduced due to the smaller mass to be accelerated.

[0045] In a further embodiment of the invention, the application is a simple, process-reliable weft thread change, without having to forego the properties and advantages described above according to the preceding embodiment. The weft drive according to this embodiment is used in a weaving machine with a weft thread change. As described in WO2012 / 163571 A2, the weft threads to be read into the weft needle provided with a fork are brought into the insertion or removal position by means of the movement of selected shafts 32 and 35. However, with such a weft drive, as can be seen from Figures 10a, 10b and 11a to 11i, it is not possible to use the normal shaft change times for this purpose. Instead, the shaft change time must be selected earlier for the removal and later for the insertion, as shown in Figure 3 of WO 2012 / 163571 A2. This is unproblematic with electronically controlled shafts.However, for mechanically operated shafts 32 and 35, special eccentrics or chain links are required, and setting up the machine is correspondingly complicated.

[0046] Since much more time is available for changing the weft threads in the weft drive according to the embodiment shown in Figures 1 and 7, and since the weft needle 42 performs a small return stroke movement in the direction of the fabric as described above, it is possible to use the normal shaft change times for the weft thread change. This greatly simplifies machine setup and makes the weft thread change process more reliable. As shown in Figure 7, the weft needle is open towards the shafts (fork 43). The weft thread guides 36 and 33 connected to the foremost shafts 32 and 35 are moved by the shaft movement in such a way that the desired weft color is read into or read out of the open weft needle at the desired time, see Figures 8a, 8b, 9a to 9i. In Figure 8a the weft needle movement and in Fig. 8b the strokes of the two weft thread control shafts 32 and 35 or selection needles 36 and 33 are recorded.The zero line of the vertical axis in Fig. 8b corresponds to the height of the plane of movement of the weft needle 42. The selection of the first weft thread takes place in position A, at a machine angle of approximately 325 degrees, at a time when the weft needle is in its return stroke. The corresponding control shaft 35 or the selection needle 33 connected to it are at this time moving downwards and are located slightly below the weft needle (height -HA). As can be seen from Figure 9d, the open fork 43 of the weft needle tip crosses the section FG at this time, so that weft thread 34 is no longer held by the fork 43 and falls out of it downwards. As the movement continues, the weft needle continues its return stroke movement in the direction of the fabric for a short while. Control shaft 32 orThe selection needle 36 connected to it is moving upwards at this time and is already slightly above the weft needle level, so that the weft thread 37 is gently looped around the weft needle 42 from below, as shown in Figure 9e. Figure 9f shows how the weft thread 37 jumps into the fork 43 when the fork crosses the path KL during its renewed movement away from the fabric. See also position E in Fig. 8a or stroke HE in Figure 8b. The weft thread 37 subsequently remains in the fork 43 and is inserted into the shed until the control shaft 32 or the selection needle 36 connected to it move downwards again.

[0047] What happens when, with a previous weft drive, the weft thread change is to be carried out using the normal shaft change times is shown in Fig. 10a, 10b and 11a to 11i. As shown in Fig. 11f or Fig. 10a / 10b (position A), the reading out of the first weft thread 34 takes place at a machine angle of approximately 40 degrees. According to Figure 10b, the reading in of the second weft thread 37 would in principle be possible from a machine angle of approximately 320 degrees, since from this point on the selection needle 36 is above the plane of movement of the weft needle. However, since the fork 43 of the weft needle 42 has already passed the weft thread 37 presented for reading in at 320 degrees, it is not taken along by the fork.When the weft needle moves back toward the fabric after the reversal point, the selection needle 36 has already moved upwards so far that the presented weft thread 37 is pierced by the weft needle 42 and is also not taken along by the fork 43 (see Figures 11g and 11h). The weft needle therefore moves into the shed without a weft thread—the weft exchange process was unsuccessful.

[0048] A further embodiment is shown in Figure 12 and, with the measures of the invention, results in more reliable insertion of a guide needle piercer 52 in a machine with the incorporation of knitting threads 60. The delayed entry of the weft needle 42 into the shed 18 is very advantageous in a machine equipped with a device for incorporating knitting threads 60. With this device, at least one guide needle piercer 52 pierces the open shed 18 from above as needed and brings a knitting or effect thread 60 into the lower shed in such a way that it is pierced over by the weft needle 42 and thus incorporated into the fabric 20. The guide needle piercer 52 pivots forwards and backwards in the warp direction synchronously with the reed 10. At the time of the reed beat-up, it must be raised far enough that it does not collide with the comb shaft 53, which extends above the weaving point in the weft direction.The guide needle piercer 52 has little time available for the piercing movement (typically approximately 90 degrees machine angle), since it can only begin this after the reed beat-up and must already be sufficiently deep in the lower shed 61 before crossing with the weft needle 42. The delayed weft needle insertion increases the available time by approximately 25%, which allows the guide needle piercer 52 to penetrate deeper and thus produce a larger and more reliable knitting thread shed.

[0049] List of reference symbols

[0050] 10 reeds

[0051] 12 Drive motor

[0052] 13 Crank drive

[0053] 14 Warp thread feed

[0054] 15 Web site

[0055] 16 vocational training facility

[0056] 18 sheds

[0057] 20 fabrics

[0058] 24 weft threads

[0059] 26 warp threads

[0060] 30 Device for weft thread change

[0061] 32 Shaft 1

[0062] 33 Weft thread selection needle 2

[0063] 34 weft thread 2

[0064] 35 Shaft 2

[0065] 36 Weft thread selection needle 1

[0066] 37 weft thread 1

[0067] 38 Shaft 3

[0068] 39 Shaft 4

[0069] 40 weft thread insertion device

[0070] 42 weft needle

[0071] 43 Fork

[0072] 44 firing shaft lever

[0073] 45 Main shaft

[0074] 46 Knee lever system

[0075] 47 wave of shots

[0076] 50 Device for incorporating knitting threads

[0077] 52 pinhole needles

[0078] 53 Comb wave

[0079] 60 knitted or effect threads

[0080] 61 lower compartment

Claims

Patent claims 1. Weaving machine with at least one main shaft (45) with a crank drive (13), a warp thread feed (14), a weaving station with a shedding device (16) for forming a shed (18), a reed (10), a weft thread insertion device (40) with a weft needle (42) and a weft shaft lever (44), wherein the weft thread insertion device (40) is operatively connected to the main shaft (45) of the weaving machine by means of the crank drive (13), characterized in that a toggle lever system (46) is arranged between the crank drive (13) and the weft shaft lever (44), and the weft thread insertion device (40) further comprises a second lever system for driving the weft needle (42), wherein the action of the toggle lever changes the movement of the weft needle (42) in such a way that it enters the shed (18) with a delay and / or exits therefrom prematurely.

2. Weaving machine according to claim 1, characterized in that the weft needle insertion device (40) is also designed such that the weft needle (42) executes a return stroke movement in the fabric direction when it is located outside the shed (18).

3. Weaving machine according to claim 1 or 2, characterized in that the weaving machine further comprises a device for changing the weft thread, preferably by means of the movement of selected shafts (32, 35) and selection needles (36, 33) respectively associated with the shafts.

4. Weaving machine according to claim 3, characterized in that the tip of the weft needle (42) is provided with a fork (43), and the weaving machine is arranged so that the weft threads (36, 33) to be read in are brought into the reading or unreading position by means of the movement of the selected shafts (32, 35).

5. Weaving machine according to claim 4, characterized in that the weaving machine is set up so that the weft thread (34) can be picked out at a machine angle of 315 to 335°, preferably of 320 to 330°, at a time when the weft needle (42) is in the return stroke movement.

6. Weaving machine according to claim 5, characterized in that the weaving machine is arranged so that the corresponding control shaft (35) and the selection needle (33) connected to the control shaft (35) are in downward movement at the time of selection and are located slightly below the weft needle (height -HA).

7. Weaving machine according to claim 6, characterized in that the weaving machine is set up so that the open fork (43) of the weft needle tip is positioned at this time of selection so that the weft thread (34) is no longer held by the fork (43) and falls out of it downwards.

8. Weaving machine according to claim 7, characterized in that the weaving machine is set up in such a way that in the further course of movement the weft needle (42) continues the return stroke movement in the direction of the fabric, while the control shaft (32) and the selection needle (36) connected to it in the upward movement are already above the weft needle plane, so that the weft thread (37) is easily looped around the weft needle from below.

9. Weaving machine according to claim 8, characterized in that the weaving machine is set up in such a way that the weft needle (42) ends its return stroke movement in the further course of movement and moves away from the fabric again, whereby the weft thread (37) slightly looped around the weft needle (42) from below slides in the direction of the open fork (43) until he finally jumps into the open fork (43) and is carried along by it.

10. Weaving machine according to one of claims 1 to 9, characterized in that the weaving machine further comprises a device (50) for incorporating knitting threads, by means of which guide needle piercers (52) selectively introduce knitting or effect threads (60) from above into the open shed (18) in such a way that they are pierced by the weft needle (42) and thus incorporated into the fabric.

11. Weaving machine according to claim 10, characterized in that the weaving machine is designed so that the entry of the weft needle (42) into the shed (18) is delayed by means of the toggle lever system (46) and the guide needle piercer (52) pivots forwards and backwards in the warp direction synchronously with the reed.

12. Weaving machine according to claim 1 1, characterized in that the weaving machine is set up so that the time available to the guide needle piercer (52) for introducing the knitting thread (60) into the lower shed (61) is increased by at least 20%, preferably by at least 25%, due to the delayed weft needle insertion.

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