Positive yarn feeder, particularly for yarn feeding devices of warping machines

Abstract

An electric motor (14) is fixed to a support and rotates a yarn bobbin (16) that extends around a shaft (A) and has a peripheral winding surface (16a) onto which yarn (Y) is wound. A guide (32) partially surrounds the yarn bobbin (16) and has a guide surface (32a) that faces the peripheral winding surface (16a) to form an intermediate space (33) that guides the insertion and deformation, around the yarn bobbin (16), of a weft take-up rod (P). The guide (32) has a free entry end (32') and a free exit end (32'') that form, between the peripheral winding surface (16a) and the guide surface (32a), an entry channel (34') and an exit channel (34'') for the weft take-up rod (P), respectively.

Description

Positive yarn feeder, in particular for yarn feeding apparatus of warping machines

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

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

[0003] A spool generally comprises a battery of reels supported by a frame extending over a vertical plane. The reels are usually arranged in multiple horizontal rows, for example, eight horizontal rows each containing one hundred reels, for a total of 800 reels supported by a single spool.

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

[0005] Each of the threads can be fed in a controlled manner from the reel to the warping machine by means of a respective motorized thread winding reel mounted on the creel.

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

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

[0008] Document EP 4265831 A1, a prior art document within the terms of Article 54(3) of the EPC, filed by the same applicant, provides for feeding 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 reel and incorporates a respective tension sensor. All the yarn feeder arrays are supported at one longitudinal exit 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 reels coaxial with each other.

[0009] The solution or embodiment described in document EP 4265831 A1 has the advantage of allowing the actual tension at which the yarns are fed to the warping machine to be adjusted with high precision and flexibility.

[0010] However, a drawback of this solution is that the laterally adjacent arrangement of yarn feeders belonging to the same die at a short distance can make threading the yarn feeder awkward. In particular, during threading operations, the yarn must be manually inserted through an inlet yarn guide eyelet located directly upstream of the yarn winding reel, then wound around the yarn winding reel, rested on the tension sensor, and finally inserted through an outlet yarn guide eyelet located directly downstream of the yarn winding reel.

[0011] To facilitate threading operations, the operator may use a so-called "thread guide rod," which essentially consists of a long, flexible needle with a notched end to which the thread to be threaded can be attached. However, while threading operations on the thread feeder at one end of the die may be relatively easy for the operator, since the thread guide eyelets and the thread winding bobbin are exposed and more easily accessible, the same cannot be said for the other thread feeders, where access to the thread guide eyelets and the thread winding bobbin is partially obstructed by adjacent feeders.

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

[0013] This circumstance further complicates threading operations, taking into account 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 they are, and in certain joints he may need to hold onto the ladder with one hand and therefore has only one free hand for threading operations.

[0014] In view of the foregoing, the objective of the present invention is to provide a positive thread feeder, particularly for thread feeding apparatus for forming machines, which facilitates threading operations, especially in relation to the use of said thread feeder in association with others arranged laterally adjacent to each other and a short distance within a die.

[0015] The above purpose and other objectives that will be more evident below in this document are achieved by means of a positive thread feeder having the characteristics set forth in claim 1, while the subordinate claims define other advantageous, though secondary, features 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, in which: Figure 1 is a side elevation view of a positive wire feeder according to the invention; Figure 2 is a partially sectional front elevation view of the positive wire feeder of Figure 1; Figure 3 is a plan view of the positive wire feeder of Figure 1; Figure 4 is a view, similar to Figure 1, showing the positive thread feeder during a first threading stage; Figure 5 is a perspective view of the positive thread feeder of Figure 4; Figure 6 is a view, similar to Figure 1, showing the positive thread feeder during a second threading stage; Figure 7 is a perspective view of the positive thread feeder of Figure 6; Figure 8 is a view, similar to Figure 1, showing the positive thread feeder during a third threading stage; Figure 9 is a perspective view of the positive thread feeder of Figure 8; Figure 10 is a view, similar to Figure 1, showing the positive thread feeder during a fourth threading stage; Figure 11 is a perspective view of the positive thread feeder of Figure 10; Figure 12 is a view, similar to Figure 1, showing the positive thread feeder during a fifth threading stage; Figure 13 is a perspective view of the positive thread feeder of Figure 12; Figure 14 is a perspective view of a series of identical positive wire feeders arranged laterally adjacent to each other and separated by a short distance within an array; Figure 15 is a view, similar to Figure 1, showing a positive thread feeder according to another embodiment of the invention; Figure 16 is a partially sectioned front elevation view of the positive wire feeder of Figure 15; Figure 17 is a plan view of the positive wire feeder of Figure 15.

[0017] Referring to Figures 1 to 3, a positive wire feeder, hereinafter referred to as the "feeder" 10 for brevity, comprises a support 12, an electric motor 14 fixed to the support 12, and a wire winding reel 16 extending about an axis A, which is functionally connected to the electric motor 14 in order to be rotated by the latter. The wire winding reel 16 has a peripheral winding surface 16a on which a wire Y is adapted for winding.

[0018] In this form of realization: Support 12 comprises a plate 18, The thread winding reel 16 is supported on one side of plate 18 with its axis A perpendicular to plate 18 and has an axial cavity 24 (Figure 2) in which the electric motor 14 is housed, and The electric motor 14 is provided with an external stator 20, which forms a single piece with the plate 18, and an internal rotor 22 (shown only schematically in Figures 1 and 2), to which the wire winding reel 16 is connected, the stator 20 and the rotor 22 extending around the same axis A as the wire winding reel 16.

[0019] The arrangement described above allows minimizing the axial footprint of feeder 10, making it particularly suitable for use in association with other identical feeders arranged laterally adjacent to each other and a short separation distance within a matrix, as shown in Figure 14.

[0020] In this embodiment, the feeder 10 is provided with an inlet thread guide eyelet 26 and an outlet thread guide eyelet 28 which are fixed to the plate 18 upstream and downstream of the thread winding reel 16, respectively, with respect to the thread feed direction Y.

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

[0022] The thread arriving at the feeder 10 passes through the incoming thread guide eyelet 26, is wound one or more times on the thread winding reel 16 (only once in the embodiment shown in Figures 4 to 13, which will be discussed below in this document), is coupled with the tension sensor 30 and finally passes through the outgoing thread guide eyelet 28.

[0023] As shown in Figures 4 to 13 below in this memorandum, to facilitate threading operations, the operator may make use of a threading rod, referred to more briefly below in this memorandum as the P rod, which essentially consists of a long flexible needle provided with a notched end P to which the thread to be threaded can be attached.

[0024] According to the invention, in order to facilitate threading operations, the feeder 10 comprises a guide 32 that partially surrounds the thread winding reel 16 and has a guiding surface 32a that faces the peripheral winding surface 16a to form an intermediate space 33 adapted to guide the insertion and deformation, around the thread winding reel 16, of the rod P, said guide 32 having a free entry end 32 and a free exit end 32 that define, between the peripheral winding surface 16a and the guiding surface 32a, an entry passage 34 and an exit passage 34 for the rod P, respectively.

[0025] Preferably, the guide 32 surrounds a sector of the thread winding reel 16 on the opposite side of axis A with respect to the inlet thread guide eyelet 26.

[0026] Advantageously, guide 32 features an annular sector portion that extends around axis A.

[0027] Obviously, with respect to the annular sector part 35, the definition "annular sector" refers to the profile of the guide surface 32a in that part, since externally the guide 32 can have any suitable profile.

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

[0029] Advantageously, the guide 32 has a straight entry portion 36 that extends tangentially from the annular sector portion 35 on the free entry end side 32, so that the entry passage 34 is widened and the insertion of the rod P is made easier.

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

[0031] Evidently, even with respect to the straight parts, the definition "straight" refers to the profile of the guide surface 32a in that part, since externally the guide 32 can have any suitable profile.

[0032] Preferably, the guide 32 has an overall angular extent (i.e., the annular sector portion 35, the straight entry portion 36 and the straight exit portion 36") between 90° and 270°, more preferably about 200° (Figure 1).

[0033] In this embodiment, the peripheral winding surface 16a of the wire winding reel 16 has a cylindrical profile suitable for accommodating possibly multiple turns of wire side by side, although in the embodiment described herein and shown in Figures 4 to 13, which will be discussed below in this document, 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 lower cylindrical surface 32a delimited laterally between two mutually opposing truncated conical surfaces 32a, 32a, which are adapted to guide and laterally retain the rod P during threading operations.

[0035] Figures 4 to 13 show five stages of threading operations in sequence.

[0036] In Figures 4 and 5, the notched end P of rod P is inserted into the intermediate space 33 formed between the thread winding reel 16 and the guide 32 through the entry passage 34.

[0037] In Figures 6 and 7, the rod P is pushed into the intermediate space 33 until it comes out of the exit step 34" and then inserted into the incoming thread guide loop 26 in the opposite direction to the thread's displacement direction, after which the thread Y is hooked onto the notched end P.

[0038] In Figures 8 and 9, the rod P, with the thread hooked onto it, is pushed back into the intermediate space 33 in the opposite direction with respect to the previous stages until it comes out of the entry step 34, after which it is pulled so that the thread Y passes over the tension sensor 30, and then inserted into the exit thread guide eyelet 28 in the direction of thread movement.

[0039] If it is desired to wind multiple turns of thread Y onto the thread winding reel 16, before passing thread Y over the tension sensor 30 and inserting rod P into the output thread guide eyelet 28, the rod P is inserted back into the intermediate space 33 through the output passage 34 and pulled out of the input passage 34, repeating the operation several times corresponding to the number of turns of thread Y that are to be wound.

[0040] In Figures 10 and 11, pull rod P until thread Y is pulled out of the output thread guide eyelet 28.

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

[0042] As those skilled in the art will appreciate, the feeder 10 according to the invention fully achieves its intended purpose and objective. 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 separated by a short distance within a matrix. Figure 14 schematically shows a matrix of such feeders 10 attached to a generic structure F, for example, the frame of a creel.

[0043] Once the rod has been inserted between the thread winding reel and the guide, an operator can easily maneuver the rod even with one hand according to the steps shown in Figures 4 to 13, thanks to the guide that properly directs the rod around the thread winding reel.

[0044] The foregoing applies both to the feeder positioned at the end of the die with the respective thread winding spool exposed externally (i.e., the rightmost feeder 10 in Figure 14) and to feeders in internal positions or at the opposite end of the die, with respect to which the advantages of the present invention are even more apparent. In fact, access to the thread guide eyelets and the thread winding spool of such feeders is partially obstructed by adjacent feeders, and as a result, the presence of the guide considerably facilitates threading operations.

[0045] As the expert in the field will appreciate, the advantages of the invention become even more apparent as the number of feeders belonging to the array increases. This is because, as described in the preamble to this description, the difficulty for the operator to access the feeders increases as the length of the array increases.

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

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

[0048] The feeder 110 according to this alternative embodiment differs from the previous embodiment only in that the peripheral winding surface 116a of the wire winding reel 116 has a concave profile, advantageously a V-shaped profile delimited between two mutually opposing truncated conical walls 116a, 116a, while the guiding surface 132a of the guide 132 has a cylindrical profile.

[0049] The remaining elements of the 110 feeder may 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 wire.

[0051] Threading operations can be performed in a similar manner to the above embodiment, the only difference being that during threading operations, the function of laterally guiding the rod in this case is performed by the truncated conical walls 116a, 116a of the peripheral winding surface 116a of the reel.

[0052] Some preferred embodiments of the invention have been described, but of course, a 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 guide surface of the guide could 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, an arc-shaped circular profile, and the like.

[0054] The winding surface of the reel may also have a concave profile that differs 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, an arc-shaped circular profile, and the like. The winding surface of the reel may also have raised portions adapted to increase friction with the wire, for example, alternating sets of teeth on two opposing surfaces that laterally define the winding surface itself.

[0055] Obviously, depending on the specific application, the guide surface of the guide and the winding surface of the reel may also have concave profiles or both be cylindrical.

[0056] Furthermore, the invention has been shown to be particularly advantageous in relation to feeders that have a flattened shape and are intended for use in conjunction with other identical feeders within a matrix whose longitudinal footprint needs to be limited as much as possible. However, the invention can also be advantageously applied to more traditional feeders in which, for example, the reel is conventionally keyed to the shaft of an electric motor arranged coaxially in front of the reel rather than being accommodated within it. In this case, the support can coincide with the motor housing of the motor itself.

[0057] In particular, the angular extension of the guide can be varied according to the specific application.

[0058] Where the technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of enhancing the intelligibility of the claims and, consequently, those reference signs have no limiting effect on the interpretation of each element identified by example by those reference signs.

Claims

1. A positive thread feeder comprising a support (12), an electric motor (14) fixed to the support, and a thread winding reel (16) extending around a shaft (A), which is functionally connected to the electric motor (14) and driven by its rotation, and is provided with a peripheral winding surface (16a) onto which a thread (Y) is adapted for winding, characterized in that it comprises a guide (32) partially surrounding said thread winding reel (16) and is provided with a guiding surface (32a; 132a) facing said peripheral winding surface (16a) so as to form an intermediate space (33) adapted to guide the insertion and deformation, around the thread winding reel (16), of a thread guide rod (P), said guide (32) having a free entry end (32) and a free exit end (32) forming,between said peripheral winding surface (16a; 116a) and said guiding surface (32a), an entry passage (34) and an exit passage (34) for said thread guide rod (P), respectively.

2. Positive thread 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. Positive thread feeder according to claim 2, characterized in that said annular sector portion (35) has an angular extension of between 90° and 270°.

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

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

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

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

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

9. 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. Positive wire feeder according to claim 9, characterized in that said guiding surface (32a) has a trapezoidal concave profile with a lower cylindrical surface (32a) laterally delimited between two mutually opposing frustoconical surfaces (32a”, 32a).

11. Positive wire 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. Positive wire feeder according to claim 11, characterized in that said peripheral winding surface (116a) has a V-shaped profile delimited between two mutually opposing frustoconical walls (116a, 116a”).

13. Positive thread feeder according to claim 12,characterized in that it comprises an inlet thread guide eyelet (26) and an outlet thread guide eyelet (28) that are fixed to said support (12) respectively upstream and downstream of said thread winding reel (16) with respect to a thread feed direction (Y), said guide (32) surrounding a sector of said thread winding reel (16) on an opposite side of said axis (A) with respect to the inlet thread guide eyelet (26).

14. Positive thread feeder according to claim 12, characterized in that said support (12) comprises a plate (18), said thread winding reel (16) being supported on one side of said plate (18) with its axis (A) perpendicular to said plate (18) and having an axial cavity (24) in which said electric motor (14) is housed,and said electric motor (14) being provided with an external stator (20) which is formed in one piece with said plate (18) and with an internal rotor (22) to which said wire winding reel (16) is connected, said stator (20) and said rotor (22) extending around said axis (A).

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