POSITIVE THREAD SUPPLY DEVICE, ESPECIALLY FOR THREAD SUPPLY DEVICES FOR SHARPENING MACHINES

Description

[0001] The present invention relates to a positive yarn feeder particularly for yarn feeding apparatuses for warping machines.

[0002] As is known, a plurality of yarns can conventionally be fed to a warping machine by one or more creels.

[0003] A creel generally comprises a battery of spools supported by a frame extending on a vertical plane. The spools are generally arranged in multiple horizontal rows, e.g., eight horizontal rows each containing one hundred spools, for a total of eight hundred spools supported by a single creel.

[0004] Typically, the warping machine can be fed by a pair of creels of the above type placed opposite to each other.

[0005] Each one of the yarns can be fed in a controlled manner from the spool to the warping machine by means of a respective motorized yarn winding spool mounted on the creel.

[0006] The rotation rate of each yarn winding spool is normally adjusted by control means on the basis of the signals received from at least one tension sensor that is functionally arranged between the yarn winding spool and the warping machine, in order to stabilize yarn tension at a fixed or variable predetermined level.

[0007] EP 2 664 569 A1 discloses a positive yarn feeder according to the preamble of claim 1.

[0008] EP 4 265 831 A1, state of the art falling within the terms of Art. 54(3) EPC, in the name of this same Applicant devises to feed the yarns from the creels to the warping machine by means of multiple arrays of so-called "positive" yarn feeders, each of which is equipped with a respective motorized yarn winding spool and incorporates a respective tension sensor. The arrays of yarn feeders are all supported at a longitudinal output end of the creel. The yarn feeders of each array are arranged laterally adjacent to each other and at a short distance apart, with their respective yarn winding spools coaxial to each other.

[0009] The solution or embodiment described in EP 4 265 831 A1 has the advantage of allowing to adjust with high precision and flexibility the actual tension at which the yarns are fed to the warping machine.

[0010] However, one drawback of this solution is that the laterally adjacent arrangement at a short distance apart of the yarn feeders belonging to the same array can make yarn feeder "threading" operations awkward. In particular, in threading operations the yarn must be inserted manually through an input yarn guiding eyelet located directly upstream of the yarn winding spool, then wound around the yarn winding spool, resting on the tension sensor, and finally inserted through an output yarn guiding eyelet located directly downstream of the yarn winding spool.

[0011] To facilitate threading operations, the operator can make use of a so-called "weft taker rod", which essentially consists of a long flexible needle provided with a notched end to which the yarn to be threaded can be hooked. Nonetheless, while threading operations on the yarn feeder located at one end of the array may be relatively easy for the operator, since the yarn guiding eyelets and the yarn winding spool are exposed and more easily accessible, the same cannot be said for the other yarn feeders, where access to the yarn guiding eyelets and the yarn winding spool is partially hindered by the adjacent feeders.

[0012] It should also be considered that each array may comprise several dozen yarn feeders and, as a result, be more than one meter long. In these cases, the operator, during threading operations, in order to access the rear side of the yarn feeders located in the innermost positions, cannot go around the array laterally (i.e., at the ends) with his arms, because the length of the array does not allow this, but he can only "climb over" the array from above or below.

[0013] Such a circumstance further complicates threading operations, considering also that in many cases the operator performs such operations on a work ladder at a height of a few meters, in conditions that are already quite uncomfortable as it is, and at certain junctures he may need to hold on to the ladder with one hand and thus has only one hand free for threading operations.

[0014] In view of the above, the aim of the present invention is to provide a positive yarn feeder, particularly for yarn feeding apparatuses for warping machines, that makes threading operations easier, especially in relation to the use of such a yarn feeder in association with others arranged laterally adjacent to each other and at a short distance apart within an array.

[0015] The above aim and other objects that will become more apparent hereinafter are achieved by a positive yarn feeder having the characteristics set forth in claim 1, while the dependent claims define other advantageous, albeit secondary, characteristics of the invention.

[0016] The invention will now be described in greater detail, with reference to some preferred but not exclusive embodiments thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is a lateral elevation view of a positive yarn feeder according to the invention; Figure 2 is a partially sectional front elevation view of the positive yarn feeder of Figure 1; Figure 3 is a plan view of the positive yarn feeder of Figure 1; Figure 4 is a view, similar to Figure 1, showing the positive yarn feeder during a first threading step; Figure 5 is a perspective view of the positive yarn feeder of Figure 4; Figure 6 is a view, similar to Figure 1, showing the positive yarn feeder during a second threading step; Figure 7 is a perspective view of the positive yarn feeder of Figure 6; Figure 8 is a view, similar to Figure 1, showing the positive yarn feeder during a third threading step; Figure 9 is a perspective view of the positive yarn feeder of Figure 8; Figure 10 is a view, similar to Figure 1, showing the positive yarn feeder during a fourth threading step; Figure 11 is a perspective view of the positive yarn feeder of Figure 10; Figure 12 is a view, similar to Figure 1, showing the positive yarn feeder during a fifth threading step; Figure 13 is a perspective view of the positive yarn feeder of Figure 12; Figure 14 is a perspective view of a series of identical positive yarn feeders arranged laterally adjacent to each other and a short distance apart within an array; Figure 15 is a view, similar to Figure 1, showing a positive yarn feeder according to another embodiment of the invention; Figure 16 is a partially sectional front elevation view of the positive yarn feeder of Figure 15; Figure 17 is a plan view of the positive yarn feeder of Figure 15.

[0017] With reference to Figures 1-3, a positive yarn feeder, henceforth referred to as "feeder" 10 for brevity, comprises a support 12, an electric motor 14 fixed to the support 12, and a yarn winding spool 16 extending around an axis A, which is functionally connected to the electric motor 14 in order to be turned by the latter. The yarn winding spool 16 has a peripheral winding surface 16a on which a yarn Y is adapted to be wound.

[0018] In this embodiment: the support 12 comprises a plate 18, the yarn winding spool 16 is supported on one side of the plate 18 with its axis A perpendicular to the plate 18 and has an axial cavity 24 (Figure 2) in which the electric motor 14 is accommodated, and the electric motor 14 is provided with an external stator 20, which is integral with the plate 18, and with an internal rotor 22 (shown only schematically in Figures 1 and 2), to which the yarn winding spool 16 is connected, the stator 20 and the rotor 22 extending around the same axis A as the yarn winding spool 16.

[0019] The above-described arrangement allows to minimize the axial footprint of the feeder 10, which makes it particularly suitable for use in association with other identical feeders arranged laterally adjacent to each other and a short distance apart within an array, as shown in Figure 14.

[0020] In this embodiment, the feeder 10 is provided with an input yarn guiding eyelet 26 and an output yarn guiding eyelet 28 which are fixed to the plate 18 upstream and downstream of the yarn winding spool 16, respectively, with respect to the feeding direction of the yarn Y.

[0021] Moreover, in this embodiment, the feeder 10 is also equipped with a tension sensor 30 arranged between the yarn winding spool 16 and the output yarn guiding eyelet 28.

[0022] The yarn arriving at the feeder 10 passes through the input yarn guiding eyelet 26, is wound one or more times on the yarn winding spool 16 (only once in the embodiment shown in Figures 4-13, which will be commented on hereinafter), engages the tension sensor 30, and finally passes through the output yarn guiding eyelet 28.

[0023] As shown in Figures 4-13 hereinafter, to facilitate threading operations the operator can make use of a weft taker rod, hereinafter referenced more briefly as rod P, which essentially consists of a long flexible needle provided with a notched end P' to which the yarn to be threaded can be hooked.

[0024] According to the invention, in order to facilitate threading operations, the feeder 10 comprises a guide 32 which partially surrounds the yarn winding spool 16 and has a guiding surface 32a which faces the peripheral winding surface 16a to form an interspace 33 adapted to guide the insertion and deformation, around the yarn winding spool 16, of the rod P, said guide 32 having a free input end 32' and a free output end 32" which define, between the peripheral winding surface 16a and the guiding surface 32a, an input passage 34' and an output passage 34" for the rod P, respectively.

[0025] Preferably, the guide 32 surrounds a sector of the yarn winding spool 16 on the opposite side of the axis A with respect to the input yarn guiding eyelet 26.

[0026] Advantageously, the guide 32 has an annular sector portion that is extended around the axis A.

[0027] Of course, as regards the annular sector portion 35, the definition "annular sector" refers to the profile of the guiding surface 32a in that portion, since externally the guide 32 may have any suitable profile.

[0028] Preferably, the annular sector portion 35 has an angular extension comprised between 90° and 270°, more preferably approximately 180°.

[0029] Advantageously, the guide 32 has a straight input portion 36' that extends tangentially from the annular sector portion 35 on the side of the free input end 32', so as to widen the input passage 34' and facilitate the insertion of the rod P.

[0030] Advantageously, the guide 32 also has a straight output portion 36" which extends tangentially from the annular sector portion 35 on the side of free output end 32" so as to widen the output passage 34" and facilitate the extraction of the rod P.

[0031] Of course, even with regard to the rectilinear portions, the definition "rectilinear" refers to the profile of the guiding surface 32a in said portion, since externally the guide 32 can have any suitable profile.

[0032] Preferably, the guide 32 has an overall angular extension α (i.e., annular sector portion 35, straight input portion 36' and straight output portion 36") comprised between 90° and 270°, more preferably approximately 200° (Figure 1).

[0033] In this embodiment, the peripheral winding surface 16a of the yarn winding spool 16 has a cylindrical profile suitable for possibly accommodating multiple turns of yarn side by side, although in the embodiment described here and shown in Figures 4-13, which will be commented on hereinafter, there is only one turn.

[0034] In this case, preferably, the guiding surface 32a of the guide 32 has a concave profile, more preferably a trapezoidal concave profile with a cylindrical bottom surface 32a' delimited laterally between two mutually opposite frustoconical surfaces 32a", 32a‴, which are adapted to guide and laterally retain the rod P during threading operations.

[0035] Figures 4-13 show five steps of the threading operations in sequence.

[0036] In Figures 4 and 5, the notched end P' of the rod P is inserted in the interspace 33 formed between the yarn winding spool 16 and the guide 32 through the input passage 34'.

[0037] In Figures 6 and 7, the rod P is pushed into the interspace 33 until it exits from the output passage 34" and then it is inserted in the input yarn guiding loop 26 in the direction opposite to the direction of yarn travel, after which the yarn Y is hooked onto the notched end P'.

[0038] In Figures 8 and 9, the rod P, with the yarn hooked onto it, is pushed again into the interspace 33 in the opposite direction with respect to the previous steps until it exits from the input passage 34', after which it is pulled so that the yarn Y passes over the tension sensor 30, and then it is inserted in the output yarn guiding eyelet 28 in the direction of yarn travel.

[0039] If one wishes to wind multiple turns of yarn Y on the yarn winding spool 16, before passing the yarn Y over the tension sensor 30 and inserting the rod P into the output yarn guiding eyelet 28, the rod P is inserted again in the interspace 33 through the output passage 34" and extracted from the input passage 34', repeating the operation a number of times that corresponds to the number of turns of yarn Y that one wishes to wind.

[0040] In Figures 10 and 11, the rod P is pulled until the yarn Y is extracted from the output yarn guiding eyelet 28.

[0041] In Figures 12 and 13, the yarn is released from the eyelet, with the threading operations on the feeder 10 thus completed.

[0042] As the person skilled in the art will appreciate, the feeder 10 according to the invention fully achieves its intended aim and object. In particular, the guide 32 considerably facilitates threading operations, especially when the feeder 10 is used in conjunction with other identical feeders arranged laterally adjacent to each other and a short distance apart within an array. Figure 14 shows schematically such an array of feeders 10 fixed to a generic structure F, for example the frame of a creel.

[0043] Once the rod has been inserted between the yarn winding spool and the guide, an operator can easily maneuver the rod even with one hand according to the steps shown in Figures 4-13, by virtue of the guide which properly directs the rod around the yarn winding spool.

[0044] The above applies to both the feeder placed at the end of the array with the respective yarn winding spool exposed externally (i.e., the rightmost feeder 10 in Figure 14) and to feeders in inner positions or at the opposite end of the array, with respect to which the advantages of the present invention are even more appreciable. In fact, access to the yarn guiding eyelets and to the yarn winding spool of said feeders is partially hindered by the adjacent feeders, and as a result the presence of the guide considerably facilitates threading operations.

[0045] As the person skilled in the art will appreciate, the advantages of the invention are all the more appreciable as the number of feeders belonging to the array increases. This occurs because, as described in the preamble of this description, the difficulty for the operator to access the feeders increases as the length of the array increases.

[0046] In addition, the advantages of the invention are even more appreciable when the operator has to perform the threading operations at a considerable height, for example on a ladder. In fact, the possibility to maneuver the rod with a single hand allows the operator to hold onto the ladder with the other hand, improving the comfort and safety conditions under which threading operations are performed.

[0047] Figures 15-17 show an alternative embodiment of the feeder according to the invention. The elements that correspond to those of the previous embodiment are designated by the same reference numerals increased by 100.

[0048] The feeder 110 according to this alternative embodiment differs from the one of the previous embodiment only in that the peripheral winding surface 116a of the yarn winding spool 116 has a concave profile, advantageously a V-shaped profile delimited between two mutually opposite frustoconical walls 116a', 116a", while the guiding surface 132a of the guide 132 has a cylindrical profile.

[0049] The remaining elements of the feeder 110 can be identical to those of the previous embodiment and therefore their description will not be repeated.

[0050] The V-shaped profile of the peripheral winding surface 116a is adapted to accommodate a single turn of yarn.

[0051] The threading operations can be performed similarly to the previous embodiment, the only difference being that during the threading operations, the function of laterally guiding the rod in this case is performed by the frustoconical walls 116a', 116a" of the peripheral winding surface 116a of the spool.

[0052] Some preferred embodiments of the invention have been described, but of course the person skilled in the art may apply various modifications or variations within the scope of the claims.

[0053] For example, depending on the circumstances, the guiding surface of the guide might have a concave profile that is different from the V-shaped profile of the second embodiment described, such as a U-shaped profile with a flat or concave bottom, a trapezoidal concave profile, a circular arc-like profile, and the like.

[0054] The winding surface of the spool might also have a concave profile that is different from the trapezoidal concave profile of the first embodiment described, such as a U-shaped profile with a flat or concave bottom, a V-shaped profile, a circular arc-like profile, and the like. The winding surface of the spool might also have raised portions adapted to increase friction with the yarn, e.g., alternating sets of teeth on two opposite surfaces that laterally delimit the winding surface itself.

[0055] Of course, depending on the specific application, the guiding surface of the guide and the winding surface of the spool might also both have concave profiles or be both cylindrical.

[0056] Moreover, it has been shown that the invention is particularly advantageous in relation to feeders having a flattened shape and intended to be used in association with other identical feeders within an array the longitudinal footprint of which needs to be limited as much as possible. However, of course, the invention may also advantageously apply to more traditional feeders in which, for example, the spool is conventionally keyed on the shaft of an electric motor arranged coaxially in front of the spool instead of being accommodated inside it. In this case, the support may coincide with the motor body of the motor itself.

[0057] Not least, the angular extension of the guide can be varied according to the specific application.

[0058] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A positive yarn feeder comprising a support (12), an electric motor (14) fixed to the support, and a yarn winding spool (16) extended around an axis (A), which is functionally connected to the electric motor (14) to be driven in rotation by it and is provided with a peripheral winding surface (16a) on which a yarn (Y) is adapted to be wound, characterized in that it comprises a guide (32) which partially surrounds said yarn winding spool (16) and is provided with a guiding surface (32a; 132a) which faces said peripheral winding surface (16a) so as to form an interspace (33) adapted to guide the insertion and deformation, around the yarn winding spool (16), of a weft taker rod (P), said guide (32) having a free input end (32') and a free output end (32") which form, between said peripheral winding surface (16a; 116a) and said guiding surface (32a), an input passage (34') and an output passage (34") for said weft taker rod (P), respectively.

2. The positive yarn feeder according to claim 1, characterized in that said guide (32) is provided with an annular sector portion (35) extending around said axis (A).

3. The positive yarn feeder according to claim 2, characterized in that said annular sector portion (35) has an angular extension comprised between 90° and 270°.

4. The positive yarn feeder according to claim 3, characterized in that said annular sector portion (35) has an angular extension of substantially 180°.

5. The positive yarn feeder according to claim 2, characterized in that said guide (32) has a straight input portion (36') extending tangentially from said annular sector portion (35) on the side of said free input end (32').

6. The positive yarn feeder according to claim 2, characterized in that said guide (32) has a straight output portion (36") extending tangentially from said annular sector portion (35) on the side of said free output end (32").

7. The positive yarn feeder according to claim 1, characterized in that said guide (32) has an overall angular extension comprised between 90° and 270°.

8. The positive yarn feeder according to claim 7, characterized in that said guide (32) has an overall angular extension of substantially 200°.

9. The positive yarn feeder according to claim 1, characterized in that said peripheral winding surface (16a) has a cylindrical profile and said guiding surface (32a) has a concave profile.

10. The positive yarn feeder according to claim 9, characterized in that said guiding surface (32a) has a trapezoidal concave profile with a cylindrical bottom surface (32a') delimited laterally between two mutually opposite frustoconical surfaces (32a", 32a‴).

11. The positive yarn feeder according to claim 1, characterized in that said peripheral winding surface (116a) is provided with a concave profile and said guiding surface (132a) is provided with a cylindrical profile.

12. The positive yarn feeder according to claim 11, characterized in that said peripheral winding surface (116a) has a V-shaped profile delimited between two mutually opposite frustoconical walls (116a', 116a").

13. The positive yarn feeder according to claim 12, characterized in that it comprises an input yarn guiding eyelet (26) and an output yarn guiding eyelet (28) which are fixed to said support (12) respectively upstream and downstream of said yarn winding spool (16) with respect to a feeding direction of the yarn (Y), said guide (32) surrounding a sector of said yarn winding spool (16) on an opposite side of said axis (A) with respect to the input yarn guiding eyelet (26).

14. The positive yarn feeder according to claim 12, characterized in that said support (12) comprises a plate (18), said yarn winding spool (16) is supported on one side of said plate (18) with its axis (A) perpendicular to said plate (18) and has an axial cavity (24) in which said electric motor (14) is accommodated, and said electric motor (14) is provided with an external stator (20) which is integral with said plate (18) and with an internal rotor (22) to which said yarn winding spool (16) is connected, said stator (20) and said rotor (22) extending around said axis (A).