WO2013128479A1

WO2013128479A1 - Expandable shaft for supporting reels and the like

Info

Publication number: WO2013128479A1
Application number: PCT/IT2012/000058
Authority: WO
Inventors: Stefano Gattrugeri; Franco Pettinati
Original assignee: I.E.S. International Expanding Shafts S.R.L
Priority date: 2012-02-27
Filing date: 2012-02-27
Publication date: 2013-09-06
Also published as: EP2819941A1

Abstract

Expandable shaft (la, lb) provided with an entrainment shaft (2) and a shell (3) rotatably fitted over the entrainment shaft (2) and extending substantially for the entire length thereof. The shell (3) comprises openings (13) through which elements (20) can protrude for removably locking the core (4) of a reel that can be fitted over the shell (3) and means (6) are further provided of activating the elements (20) by way of mutual rotation between the shell (3) and the entrainment shaft (2) in contrast with the action of elastic means (12) which act between the entrainment shaft (2) and the shell (3). The activation means (6) comprise a ramp on which a respective removable locking element (20) slides, entrained by the corresponding opening (13) with the aforementioned mutual rotation, so that the removable locking element (20) is moved radially in the opening (13) by the ramp according to the mutual position between the shell (3) and the entrainment shaft (2).

Description

EXPANDABLE SHAFT FOR SUPPORTING REELS AND THE LIKE

The present invention relates to an expandable shaft for supporting reels and the like, particularly for the winding or unwinding of reels.

Typically, in order to lock the cores of reels for the automatic winding or unwinding thereof, expandable shafts are used which comprise an elongated cylindrical body provided, on the outer surface, with a plurality of battens capable of expanding radially as a result of the action of pneumatic chambers.

A problem with this type of shaft is the centering of the shaft with respect to the core of the reels that it supports. This problem was addressed in Italian patent application no. MI2004A001298, using means for pre- centering.

However, such conventional shafts are not devoid of drawbacks, including the fact that the radial expansion of the shaft is necessarily obtained with pneumatic means, which, in addition to complicating the design and the structure of the shaft, also involves the use of supplementary means.

Moreover, the centering of the cores on the shaft is achieved with supplementary contrivances, which can increase the complexity and cost of the shaft.

The aim of the present invention consists in providing an expandable shaft for supporting reels and the like which is structurally simple so as to overcome the aforementioned drawbacks.

Within this aim, an object of the invention is to provide a shaft that is expandable by mechanical means only, without resorting to pneumatic means, and which makes it possible to always maintain a stable clamping between the core of the reel and the shaft, even if the tensioning on the reel ceases or changes.

Another object of the present invention consists in providing an expandable shaft wherein it is possible to have a particularly rapid mounting without having to resort to adopting special tools or complex solutions.

Another object of the present invention consists in providing an expandable shaft that enables an installation of the core of the reel on the shaft that can be independent of the direction of rotation of the expandable shaft during the winding or unwinding of the reel.

Another object of the present invention is to provide an expandable shaft wherein it is possible to have a particularly rapid dismounting of the reel or only of the core from the shaft.

Another object of the present invention is to achieve the centering of the shaft with respect to the reels that it supports automatically, without having to resort to supplementary means.

Another object of the present invention is to provide an expandable shaft that, owing to its peculiar implementation characteristics, is capable of offering the widest guarantees of reliability and safety in use.

Another object of the present invention is to provide an expandable shaft that can be easily implemented with simple mechanical operations starting with elements and materials that are readily available on the market, and which, moreover, is competitive from a merely economical viewpoint.

This aim and these and other objects which will become better apparent hereinafter are achieved by an expandable shaft for supporting reels and the like, particularly for the winding or unwinding of reels, characterized in that it comprises an entrainment shaft and a shell rotatably fitted over the entrainment shaft and extending substantially for the entire length of the entrainment shaft, the shell comprising openings through which elements can protrude for removably locking the core of a reel that can be fitted over the shell, means being further provided for activating the removable locking elements by way of mutual rotation between the shell and the entrainment shaft in contrast with the action of elastic means which act between the entrainment shaft and the shell, the activation means comprising a ramp on which a respective removable locking element slides entrained by the corresponding opening with said mutual rotation, so that said removable locking element is moved radially in said opening by said ramp according to the mutual position between said shell and said entrainment shaft.

The activation means can comprise a plurality of slots defined on the entrainment shaft, each one for a circumferential portion thereof, each one of the slots having a variable radial depth along the circumferential portion so as to define such ramp.

The openings of the shell are respectively overlaid on such slots.

The slots can be arranged in several longitudinal positions of the entrainment shaft. In each one of such longitudinal positions a plurality of slots can be provided, which intersect a same plane that is perpendicular to the axis of the entrainment shaft.

Advantageously, the longitudinal positions of the slots can be such that the slots are arranged mutually staggered along the entrainment shaft.

Each slot can define a first and a second ramp juxtaposed with the peak positioned between them, and the elastic means are defined by mutually opposite helical springs which are accommodated in at least one seat which is provided on the entrainment shaft and is fixed on opposite sides on an abutment which is movable together with the shell, the removable locking elements being positioned on the peak of the corresponding slot when the mutually opposite springs are in the position of equilibrium, so that the expandable shaft in its rest condition is in the expanded configuration.

Alternatively, each slot can define a first and a second ramp juxtaposed with the respective summits positioned at the opposite ends of the slot, so as to define a point of maximum depth of the slot between the first and second ramp, and the elastic means are defined by mutually opposite helical springs which are accommodated in at least one seat which is provided on the entrainment shaft and which abute on opposite sides on an abutment which is movable together with the shell, the removable locking elements being positioned on such lowest point of the corresponding slot when the mutually opposite springs are in the position of equilibrium, so that the expandable shaft in its rest condition is in the non- expanded configuration.

At least two seats can be provided for respective pairs of said mutually opposite helical springs, the seats being arranged proximate to the opposite ends of the entrainment shaft.

The removable locking elements can be partially accommodated in the slots and partially passing through the openings of the shell. Preferably, the locking elements are spheres, rollers or runners.

Further characteristics and advantages of the invention will become better apparent from the description of preferred, but not exclusive, embodiments of an expandable shaft, particularly for the winding of reels, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a perspective view of a first embodiment of the expandable shaft, particularly for the winding of reels, according to the invention;

Figure 2 is an exploded perspective view of the expandable shaft shown in Figure 1 ;

Figure 3 is a longitudinal sectional view of the expandable shaft shown in Figure 1 with a plurality of reels applied;

Figure 4 is a cross-sectional view of the expandable shaft shown in Figure 1 in its non-operative or rest configuration;

Figure 5 is a cross-sectional view of the expandable shaft shown in Figure 1 during the winding of the reels;

Figure 6 is a cross-sectional view of a second embodiment of the expandable shaft shown in Figure 1 in its non-operative configuration;

Figure 7 is a cross-sectional view of the expandable shaft in Figure 6 during the winding of the reels.

With reference to Figures 1 to 5, the expandable shaft, according to a first embodiment of the invention, which is generally designated by the reference numeral la, comprises an entrainment shaft 2 and at least one outer shell 3 which is rotatably fitted over the entrainment shaft 2 and which can be mated with at least a core 4 of a reel 5 to be wound or unwound by way of removable locking elements, preferably spheres 20 or rollers or runners, operating between the outer shell 3 and the entrainment shaft 2 and between the core 4 and the outer shell 3.

The entrainment shaft 2 can be associated with motor means, for example a rereeling machine on which the expandable shaft la operates, and can be provided with means 7 for axially locking the outer shell 3 along its longitudinal axis 9.

Such axial locking means 7 can comprise two grooves 10, provided at the ends of the entrainment shaft 2 and two spiral rings 11 accommodated in the grooves 10 and which are such as to define two axial abutment elements of the outer shell 3.

Advantageously, as will be better explained hereinafter, the spheres 20 can be activated by activation means 6 by way of a mutual rotation between the outer shell 3 and the entrainment shaft 2 in contrast with the action of elastic means 12 which act between the entrainment shaft 2 and the outer shell 3 in such a manner as to radially push outwardly the spheres 20 through openings 13 which are provided on the outer shell 3 and uniformly distributed thereon.

In the proposed embodiment, such elastic means 12 comprise at least one compression spring 14, but preferably two identical compression springs 14, which act against each other between the entrainment shaft 2 and the outer shell 3.

In more detail, for each pair of compression springs 14, an accommodation seat 15 is provided directly on the entrainment shaft 2 and extends circumferentially with respect to the entrainment shaft 2 for a circumferential arc thereof.

Moreover, located in the intermediate position of the accommodation seat 15 is an abutment dowel 16 which is movable with the outer shell 3, for example fixed inside to the outer shell 3 in such a manner as to be integral therewith in rotation. The compression springs 14 act between two opposite surfaces of the abutment dowel 16 and the two ends 17 of the accommodation seat 15.

In order to enable the insertion of the compression springs 14 in the accommodation seat 15 once the outer shell 3 is fitted over the entrainment shaft 2, on the latter an introduction portion 18 can be provided that extends longitudinally with respect to the entrainment shaft 2 and which leads, on one side, to an axial end of the entrainment shaft 2 and leads on the other side to the accommodation seat 15, centrally with respect to the circumferential extension thereof, in such a manner as to be spaced from the ends 17 of the seat 15.

More precisely, the introduction portion 18 makes it possible to perform the insertion of the compression springs 14 once the spheres 20 have been inserted, by positioning the abutment dowel 16 toward one of the ends 17 and then inserting the compression spring 14, making all of it go beyond the introduction portion 18 and allowing the expansion thereof so that the compression spring 14 is positioned against the opposite end 17 from the end toward which the dowel 16 was moved.

The compression springs 14, helical and identical to each other, are of such length as to remain preloaded in the position of equilibrium, i.e. in the non-operative or rest configuration, of the expandable shaft la, shown in Figures 1 and 4.

Moreover, the accommodation seats 15, in addition to laterally guiding the compression springs 14 and providing them with an abutment surface, are of such a length as to entirely contain the compression springs 14 in the aforementioned position of equilibrium.

In order to ensure a uniform action of the elastic means 12 along the whole longitudinal extension of the expandable shaft la, two pairs of accommodation seats 15 can be provided on the entrainment shaft 2, for example proximate to both ends of the latter.

Considering the activation means 6, in the proposed embodiment, such means comprise a plurality of first slots 19a which are provided directly on the surface of the entrainment shaft 2, each one for a circumferential portion thereof, and which have a variable radial depth along such circumferential portion.

More specifically, these first slots 19a are provided at multiple longitudinal positions of the entrainment shaft 2 so that, at each one of these, at least two first slots 19a are defined so as to be substantially equidistant from each other along the circumferential extension at the longitudinal position considered.

In the Figures, for each axial portion three first slots 19a are provided which are placed at 120° to each other on the same plane which is perpendicular to the axis of the entrainment shaft 2.

The spheres 20 are partially accommodated in the slots 19a and partially passing through the openings 13 for their partial egress through them following the mutual rotation of the outer shell 3 with respect to the entrainment shaft 2.

In particular, a sphere 20 and an opening 13 are provided for each first slot 19a.

In order to allow the insertion of the spheres 20 in the adapted slots

19a, for each assembly of slots 19a arranged axially along a same segment of the entrainment shaft 2, at least one insertion path 21 can be advantageously provided on the entrainment shaft 2 which transversely crosses the slots 19a belonging to the assembly mentioned previously.

In this manner, when mounting the outer shell 3 on the entrainment shaft 2, the individual spheres 20 are partially inserted in the respective openings 13 from within the outer shell 3 in such a way that the portions thereof which protrude into the shell 3 can slide along the sliding paths 21.

With reference to Figures 4 and 5, the bottom of each slot 19a is defined by a first ramp 22a and by a second ramp 23 a which are opposite to each other and such as to define, at their point of incidence, a minimum radial depth of the slot 19a, i.e. a peak point in the slot 19a.

Conveniently, the slots 19a and the accommodation seat 15 of the springs 14 have a symmetry with respect to their midpoint, so as to render the expandable shaft la bidirectional.

With the solution according to the first embodiment, thus, in the non- operative or rest configuration of the expandable shaft la owing to the condition of dynamic equilibrium of the elastic means 12, the spheres 20 are completely protruding from the openings 13, as shown in Figure 4. In other words, the expandable shaft la is in the completely expanded configuration when it is in the rest condition.

Moreover, with such configuration, when the core 4 of a reel is to be fitted over the outer shell 3, there must be a corresponding combined rotary and translational motion between the core 4 and the entrainment shaft 2, so that the spheres 20 can be entrained toward the deeper regions of the first slots 19a. With the cessation of the combined rotary and translational motion of the core 4 with respect to the entrainment shaft 2, thanks to the elastic means 12 the shell 3 will tend to return to the position of equilibrium, returning the spheres 20 to a position protruding outwardly from the openings 13, thus effecting the locking. As can be seen in Figure 5, the rotation of the entrainment shaft 2 during the winding of the tape on the reel 5 tends to strengthen the clamping of the core 4 on the shell 3, since it tends to pull the spheres 20 further toward the peak in the slot 19a.

In a different embodiment of the expandable shaft la, not shown in the drawings, in order to increase the number of locking elements 20 in contact with the core 4 of the reel 5, the activation means 6 can comprise a plurality of second slots identical to the first slots 19a and also defined directly on the entrainment shaft 2. Such second slots are arranged on the entrainment shaft 2 with the same arrangement as the first slots 19a but are axially and circumferentially staggered with respect to the first slots 19a, so as to optimize their distribution on the entrainment shaft.

In a second embodiment of the invention, generally designated by the reference numeral lb and shown in Figures 6 and 7, the structure and configuration of the expandable shaft lb is identical to that of the first embodiment with the sole exception of the ramps provided in the slots. In fact, in the second embodiment slots 19b are provided the bottom whereof, differently from the first slots 19a and from the second slots, is defined by a first ramp 22b and by a second ramp 23 b which are opposite to each other but such as to define, at their point of incidence, a maximum radial depth of the slot 19b. In this manner, in the non-operative or rest configuration of the expandable shaft lb owing to the condition of dynamic equilibrium of the elastic means 12, the spheres 20 are arranged at the maximum radial depth of the slots 19b, i.e. they are accommodated for the most part in the slots 19b without protruding from the openings 13, as shown in Figure 6. Alternatively, the maximum radial depth of the slots 19b can be selected so as to make the spheres 20 still protrude outwardly from the openings 13, but to such a reduced extent, for example 0.3mm, as to not prevent the core 4 from still being fitted over the shell 3. In the latter case, the spheres 20 advantageously perform the function of bearings during installation of the core 4 on the expandable shaft lb.

Conveniently, the slots 19b and the accommodation seats 15 of the springs 14 have a symmetry with respect to their midpoint, so as to render the expandable shaft lb bidirectional.

In the second embodiment, therefore, the core 4 can be fitted over the expandable shaft lb with a mutual movement of translational motion only, and the locking of the core 4 on the shell 3 is achieved with the rotation of the entrainment shaft 2, for winding, or with the tensioning of the tape to be unwound from the reel, for unwinding.

Operation of the expandable shafts la and lb is described hereinafter. With reference to Figures 4 and 5, in the expandable shaft la, starting from the non-operative or rest configuration, in which, thanks to the elastic action of the compression springs 14, the spheres 20 are located substantially on the central peak point of the slot 19a so as to protrude completely from the outer shell 3 through the openings 13.

At the moment when the core 4 of a reel to be wound is fitted on, a slight rotation can be applied to the entrainment shaft 2 with respect to the outer shell 3, in the opposite direction to that for winding the reel 5, so that the spheres 20 roll along the ramps 22a or 23 a retracting with respect to the outer shell 3. At the same time, the core 4 is made to perform a translational motion along the shell 3 until it reaches the desired position. Alternatively, starting from the rest condition and with the entrainment shaft 2 stationary, the core 4 of the reel to be wound can be fitted over the shell 3 with a combined rotary and translational motion, in which the rotary component applied to the core 4 when mounting on the shell 3 is in the direction of rotation that the entrainment shaft 2 will have when the reel is being wound, indicated in Figure 5.

In both methods of installing the core 4 on the expandable shaft la, the spheres 20 are pulled toward one of the ends of the slots 19a and, with them, the shell 3 is made to rotate with respect to the entrainment shaft 2. Subsequently, with the cessation of the combined rotary and translational motion, the springs 14 tend to make the shell 3 return to the inactive position, consequently causing the partial egress from the openings 13 of the spheres 20, which are stuck in place between one of the ramps 22a or 23 a and the inner surface of the core 4. Thus the clamping is automatically achieved of the core 4 on the expandable shaft la. During winding, thanks to the corresponding rotation obtained initially between the entrainment shaft 2 and the outer shell 3, the entrainment shaft 2 can further recover part of the above mentioned rotation, further pushing the spheres 20 out from the openings 13 of the shell 3.

In this manner a constraint is achieved on the rotation between the entrainment shaft 2 and the reel 5, which is maintained even in the event of a decrease in the pull for winding.

In order to perform the disengagement of the cores 4 from the expandable shaft la, it is sufficient to apply a slight counter-rotation of the entrainment shaft 2 with respect to the outer shell 3 so as to make the locking elements 20 retract and disengage them from the inner surface of the core 4, making it possible to unthread the cores 4 from the expandable shaft 1 a. Similarly, when the entrainment shaft 2 is stationary, the core 4 can be unthreaded therefrom with a combined rotary and translational motion of the latter.

In the second embodiment, starting from the non-operative or rest configuration, in which, thanks to the elastic action of the compression springs 14, the spheres 20 are located substantially on the point of maximum depth of the slot 19b so as to remain accommodated for the most part in the slots 19b without protruding from the outer shell 3 through the openings 13, the cores 4 can be fitted over the expandable shaft lb with a movement of translational motion only.

Once the cores are mounted, thanks to the rotation imposed by the respective motor means on the entrainment shaft 2, the entrainment shaft 2 initially rotates by a certain angle with respect to the outer shell 3 thus forcing the spheres 20 to rise along the ramps 22b or 23b and as a consequence making them protrude through the openings 13 of the shell 3, so as to make the spheres 20 stick between the ramps 22b or 23 b and the inner surface of the core 4, as shown in Figure 7.

In the second embodiment, advantageously, for a reel to be unwound and an idle entrainment shaft 2, such reel can be fitted over the expandable shaft lb without taking account of the direction of traction of the tape to be unwound from the reel.

With the arrangement described, we thus have an expandable shaft that is particularly practical and functional, in that it performs both the function of shaft for holding the reel and also the function of element for locking the reel thereto. This expandable shaft does not need any pneumatic means in order to obtain radial expansion, which instead is obtained by resorting to purely mechanical means.

Advantageously, the number of parts necessary to obtain an expandable shaft according to the invention is drastically reduced thanks also to the fact that the entrainment shaft is made in a single piece, on which the ramps necessary for the radial movement of the locking elements are provided directly.

Moreover, the structure of the shaft according to the invention makes it possible to also obtain a perfect centering of the cores, without having to use supplementary pre-centering means.

The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

Moreover, all the details may be substituted by other, technically equivalent elements.

In practice the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements.

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

Claims

1. An expandable shaft (la, lb) for supporting reels and the like, characterized in that it comprises an entrainment shaft (2) and a shell (3) rotatably fitted over said entrainment shaft (2) and extending substantially for the entire length of said entrainment shaft (2), said shell (3) comprising openings (13) through which elements (20) can protrude for removably locking the core (4) of a reel that can be fitted over said shell (3), means (6) being further provided for activating said removable locking elements (20) by way of mutual rotation between said shell (3) and said entrainment shaft (2) in contrast with the action of elastic means (12) which act between said entrainment shaft (2) and said shell (3), said activation means (6) comprising a ramp (22a, 23a, 22b, 23b) on which a respective of said removable locking element (20) slides entrained by the corresponding opening (13) with said mutual rotation, so that said removable locking element (20) is moved radially in said opening (13) by said ramp according to the mutual position between said shell (3) and said entrainment shaft (2).

2. The expandable shaft (la, lb) according to claim 1, characterized in that said activation means (6) comprise a plurality of slots (19a, 19b) defined on said entrainment shaft (2), each one for a circumferential portion of said entrainment shaft (2), each one of said slots (19a, 19b) having a variable radial depth along said circumferential portion so as to define said ramp, said openings (13) being overlaid on respective slots (19a, 19b).

3. The expandable shaft (la, lb) according to claim 2, characterized in that said slots (19a, 19b) are arranged in different longitudinal positions of said entrainment shaft (2).

4. The expandable shaft according to claim 3, characterized in that in each one of said longitudinal positions a plurality of said slots (19a, 19b) is provided, which intersect a same plane that is perpendicular to the axis of said entrainment shaft (2).

5. The expandable shaft according to claim 3 or 4, characterized in that said longitudinal positions are such that said slots (19a, 19b) are arranged mutually staggered along said entrainment shaft (2).

6. Expandable shaft (la) according to one or more of claims 2-5, characterized in that each slot (19a) defines a first and a second ramp (22a,

5 23 a) which are juxtaposed with the peak positioned between them, said elastic means being defined by mutually opposite helical springs (14), which are accommodated in at least one seat (15) which is provided on said entrainment shaft (2) and which are fixed on opposite sides on an intermediate abutment (16) which is movable together with said shell (3),0 the removable locking elements (20) being positioned on said peak of the corresponding slot (19a) when said mutually opposite springs (14) are in the position of equilibrium, so that said expandable shaft in its rest condition is in the expanded configuration.

7. The expandable shaft (lb) according to one or more of claims 2 to5 5, characterized in that each slot (19b) defines a first and a second ramp

(22b, 23b) juxtaposed with the respective summits positioned at the opposite ends of said slot (19b), so as to define a point of maximum depth between said first and second ramp (22b, 23b), said elastic means being - defined by mutually opposite helical springs (14), which are accommodated in at least one seat (15) which is provided on said entrainment shaft (2) and which are fixed on opposite sides on an intermediate abutment (16) which is movable together with said shell (3), the removable locking elements (20) being positioned on said lowest point of the corresponding slot (19b) when said mutually opposite springs (14) are in the position of equilibrium, so that said expandable shaft in its rest condition is in the non-expanded configuration.

8. The expandable shaft (la, lb) according to claim 6 or 7 characterized in that it comprises at least two of said seats (15) for respective pairs of said mutually opposite helical springs (14), said seats (15) being arranged proximate to the opposite ends of said entrainment shaft (2).

9. The expandable shaft (la, lb) according to one of claims 2 to 8, characterized in that said removable locking elements (20) are partially accommodated in said slots (19a, 19b) and partially passing through said openings (13).

10. The expandable shaft (la, lb) according to one or more of the preceding claims, characterized in that each one of said removable locking elements (20) consists of a sphere, or a roller, or a runner.