Fiber stretching device for roving frames

Abstract

Fiber stretching device for roving frames, which comprises: at least a first cylinder (1) and a second cylinder (2), both motorized, disposed in parallel in fixed positions; and a plurality of pressing arms (3), disposed in perpendicular to the motorized cylinders (1, 2) and provided with first rollers (31) and second rollers (32), both freely rotating, and upper bags (4) which embrace the corresponding freely rotating second roller (32) and support means (41) of said upper bags. The upper bags (4) press the fibers to stretch (F) directly against support zones (21) of the second motorized cylinder (2), and wherein said device does not have lower bags for the support of the upper bags (4), nor of a static track for the support of said lower bags.

Description

Technical Field

[0001] This invention finds application in the textile industry, and more particularly, in the manufacturing of fiber stretching devices or gears for roving frames.Background Art

[0002] The conventional fiber stretching device for roving frames comprises: at least first and second motorized cylinders, fixedly placed in parallel and which practically reach the full length of the roving frame; and a plurality of pressing arms perpendicular to the motorized cylinders, distributed along the roving frame, and provided with freely rotating rollers placed in parallel to said motorized cylinders.

[0003] The pressing of the fibers and their dragging in increasing speed in the advancing direction causes the stretching of the fibers, prior to their twisting or rollup in the spindles.

[0004] This stretching device comprises: a static track placed in parallel to the second motorized cylinder, and a plurality of closed belts, which we shall call "lower belts", which embrace closely the static track and the mentioned second motorized cylinder.

[0005] The pressing arms have: freely rotating first rollers and second rollers, placed in parallel and on top of the motorized cylinders, for pressing the fibers to stretch.

[0006] The second rollers of the pressing arms comprise some closed belts we call "upper belts", which embrace the corresponding second roller and means for support and tension.

[0007] The known stretching devices have means for regulating the inclination of the upper belts, and, consequently, varying the extension of its contact surface with the lower belts actioned by the second motorized cylinder.

[0008] Said lower belts are distributed along the roving frame, defining a support surface for each one of the lines of fibers to stretch, which circulate above the motorized cylinders in a perpendicular direction to said motorized cylinders.

[0009] This stretching system has regulating means for the individual adjustment of the tension of the lower belts.

[0010] A first problem identified with these lower belts is that, the adjustment of these regulating means happens to be particularly difficult and complex, taking into account: on one hand, the high number of lower belts existent in a roving frame of approximately 40m in length, and, on the other hand, that the tension of each lower belt must be sufficiently high so that all the lower belts be jointly dragged by the second motorized cylinder; however such tension should not reach a too high value to avoid that the resistance to the drag by the ensemble of lower belts provokes an excessive twisting and / or irreversible harm in said second motorized cylinder.

[0011] It should be mentioned that, with an adequate adjustment of the tension of the belts, the second motorized cylinder in charge of their actioning can be submitted to a twist of about 12 to 15 degrees between both ends of the same.

[0012] A second problem with this stretching system is the complexity involved in, and the high stop time of the roving frame necessary for, replacing said lower belts in case of wear or break, as this operation requires disassembling the second motorized cylinder and the static track along its full length, which is practically the full length of the roving frame, in order to remove the lower belts to be substituted and the subsequent assembly of the new lower belts, from one of the ends of the second motorized cylinder.

[0013] Example devices exhibiting one or more of the identified problems are disclosed in publications EP-A-0 350 797, US-A-2 751 631, DE-C-943 397, or DE-C-974 060. In particular, publication EP-A-0 350 797 refers to a drafting device comprising a first cylinder and a second cylinder, both motorized, disposed in parallel in fixed positions and identifies the problem of poor fiber guidance at the exit point of the drafting system and suggests as a solution providing a fiber guiding element 12 which offers the fibers a guide surface at the exit point.

[0014] It should be noted that the expressions such as: "first", "second", "upper", "lower", "above" or "below" are used only to facilitate differentiating the rollers, cylinders, or belts, but should not be literally interpreted as limitations on the number of position of said elements.Explanation of the invention

[0015] The fiber stretching device for roving frames object of this invention is of the afore-hand mentioned type and comprises constructional details aimed at resolving in a satisfactory manner the identified problems of the lower belts and their replacement in case of break or wear.

[0016] The solution proposed in the present invention refers to the elimination of the mentioned lower belts and of certain related elements such as: the static plaque which is embraced by said lower belts together with the second motorized cylinder, and the means for regulating the tension of said lower belts; such that the upper belts press directly the fibers to stretch against the second motorized cylinder, specifically against some support zones defined in said second motorized cylinder.

[0017] According to the invention, the current problems identified in the roving frames due to the lower belts in the stretching device or gears are resolved by eliminating the mentioned lower belts.

[0018] In one embodiment of the invention, the second motorized cylinder disposes at least in the support zones of the fibers to stretch and of the upper belts, a larger diameter than the rest of said second cylinder. This increase in diameter of the second motorized cylinder enables the upper belts not to establish a too closed curve in the contact zone with said second motorized cylinder.

[0019] The stretching device according to the invention has interchangeable spacers, of different heights, couplable to the support means of the upper belts on top of fixed stops, near the contact zones of the upper belts with said second cylinder.

[0020] Depending on the height of the spacers utilized, the upper belts have a different inclination with respect to their corresponding freely rotating roller, contacting said upper belts with larger or smaller dimensioned support zones of the second motorized cylinder.

[0021] The zones defined in the second motorized cylinder for the support of the fibers to stretch present a diameter equal to or larger than 40 millimeters, and considerably larger than the diameter of the motorized cylinders used presently in the stretching devices for roving frames, which generally are comprised between 25 and 30 millimeters.

[0022] This solution results in the stretching of the fibers once pressed by the upper belts directly against the second motorized cylinder being very similar to that achieved presently using stretching devices provided with the upper belts and lower belts with the necessary accessories for its functioning; however, this solution is more economic as the lower belts and the associated necessary accessories are eliminated, and by avoiding the problems which presently exist due to the substitution or exchange of the lower belts in case of break or wear. With this solution the twist of between 12 and 15 degrees, already mentioned, is also eliminated, which was produced between both ends of the second motorized roller.

[0023] In one embodiment of the invention, this stretching device comprises, at least, two first motorized cylinders and a second motorized cylinder for the support of the fibers to stretch, said second motorized cylinder being placed in an intermediate position between said first motorized cylinders.Brief description of the content of the drawings

[0024] With the objective of complementing the description and facilitating the understanding of the invention, the current specification is accompanied by a set of drawings in which, with illustrative and non-limiting character, the following has been represented: Figure 1 shows a schematic perspective view of a roving frame, in which the fiber stretching device or gear can be observed. Figure 2 shows a schematic view of the upper view of a section of the fiber stretching device for roving frames, according to the invention. Figure 3 shows a lateral schematic view of the stretching device of figure 2 in operating position and sectioned through a vertical A-A plane which cuts the contact zone of the upper belts with the second motorized cylinder. Figure 4 shows an analogous view of that of figure 3, with the pressing arm lifted, in inoperative position. In this figure some guides, for the grouping of the fibers disposed between the first rollers and the second motorized roller, have also been represented. Figure 5 shows a lateral view of the stretching device of figure 1 sectioned by a vertical B-B plane which cuts some of the interchangeable spacers and the corresponding fixed support stop, including also the guides for the grouping of fibers. Detailed explanation of embodiments of the invention

[0025] The fiber stretching device for roving frames, object of this invention, is applicable in roving frames (M), as the one schematically represented in figure 1, being said stretching device responsible for preparing the fibers, stretching them, aligning them, and thinning them before they are twisted and rolled up over different spindles.

[0026] In the concrete exemplary embodiment shown in figures 2 to 4, the stretching device comprises: two first cylinders (1) and a second cylinder (2), all of them motorized, disposed in parallel and fixed to the frame of the roving frame (M) in fixed positions; and a plurality of pressing arms (3), visible in figure 1, disposed in perpendicular to the motorized cylinders (1, 2) and provided of first rollers (31) and second freely rotating rollers (32), and of upper belts (4) which embrace the corresponding freely rotating second roller (32) and support means (41) of said upper belts (4).

[0027] The pressing arms (3) can be disposed in this operative position, as represented, for example, in figures 3 and 5, or in a lifted and inoperative position as represented in figure 4.

[0028] As can be observed in figure 3, in the operative position of the stretching device, the upper belts (4) press the fibers to stretch (F) directly against support zones (21) defined in the motorized second cylinder (2), lacking said stretching device lower belts for the support of the upper belts (4).

[0029] As can be observed with more detail in figure 2, the second motorized cylinder (2) presents in the support zones (21) of the fibers to stretch (F) and of the upper belts (4) a larger diameter than the rest of said second cylinder (2).

[0030] This property permits defining in the second motorized cylinder (2) adequate zones for the support and the pressing of the fibers to stretch (F) by the upper belts (4).

[0031] As can be observed in the section of figure 5, this device comprises interchangeable spacers (42), of differing heights, configured to couple to the support means (41) of the upper belts (4).

[0032] In the operative position of the stretching device, said interchangeable spacers (42) act against fixed stops (5) which permits varying the inclination of the upper belts (4) with respect to its corresponding freely rotating second rollers (32).

[0033] Depending on said inclination of the upper belts (4), said upper belts (4) contact with the second motorized cylinder (2) in support zones (21), of larger to smaller size, causing a larger or smaller retention and consequently a larger or smaller stretching of the fibers (F).

[0034] In a preferred embodiment, the diameter of the second motorized cylinder (2), at least in the support zones of the fibers to stretch, is equal or larger than 40 millimeters, thereby reducing the curve formed by the upper belts (4), in the support zones (21), with said second motorized cylinder (2).

[0035] In the shown example, and as already mentioned, the device comprises two first motorized cylinders (1) and a second motorized cylinder (2) for supporting the fibers to stretch (F), being said second motorized cylinder (2) disposed in an intermediate position between the said first motorized cylinders (1).

[0036] As shown in figures 4 and 5, this stretching device comprises in the passage zone of the fibers, concretely in-between the first motorized cylinders (1) and the second motorized cylinder (2), guides (6) for the lateral grouping of the fibers to stretch and their guiding in the forward direction.

[0037] Once the nature of the invention has been sufficiently described, as well as an exemplary preferred embodiment, it is hereby noted, for the corresponding consideration, that the materials, forms, size, and disposition of the described elements can be modified, as long as this does not suppose an alteration of the essential features of the invention which are claimed in the following.

Claims

1. Fiber stretching device for roving frames, the device comprising: at least a first cylinder (1) and a second cylinder (2), both motorized, disposed in parallel in fixed positions; a plurality of pressing arms (3) disposed in perpendicular to the motorized cylinders (1, 2), and provided with first rollers (31) and second rollers (32), both freely rotating, and with upper belts (4) which embrace the corresponding freely rotating second roller (32) and support means (41) of said upper belts, wherein the upper belts (4) are configured to press the fibers to stretch (F) directly against support zones (21) of the second motorized cylinder (2); further comprising interchangeable spacers (42), of differing heights, configured to be coupled to the support means (41) of the upper belts (4) and which, in an operative position of the stretching device, are configured to act against fixed stops (5) near the contact zones of the upper belts with respective second motorized cylinders, permitting varying the inclination of the upper belts (4) with respect to their corresponding freely rotating second rollers (32), and, depending on this inclination, said upper belts (4) are configured to contact the second motorized cylinder (2) with larger or smaller dimensioned support zones (21) causing a larger or smaller retention and consequently a larger or smaller stretching of the fibers; wherein said device does not have lower belts for the support of the upper belts (4), nor a flat static track for the support of said lower belts.

2. Device according to claim 1, wherein the second motorized cylinder (2) presents, at least in the support zones (21) of the upper belts (4) and of the fibers to stretch (F), a larger diameter than the rest of said second cylinder (2).

3. Device according to claim 2, wherein the second motorized cylinder (2) presents, at least in the support zones (21) of the fibers to stretch, a diameter equal to or larger than 40 millimeters.

4. Device according to any one of the preceding claims, comprising, at least two first motorized cylinders (1) and a second motorized cylinder (2) for the support of the fibers to stretch (F), said second motorized cylinder (2) placed in an intermediate position, in-between said first motorized cylinders (1).

Images