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Title:
TELESCOPIC LINEAR ACTUATOR OF A TYPE CONNECTABLE TO AN ARM OF A MOVABLE ARM UNWINDER
Document Type and Number:
WIPO Patent Application WO/2019/102343
Kind Code:
A1
Abstract:
A linear actuator (1) of a type connectable to an arm (101) of a movable arm unwinder (100) for reels (102); the actuator (1) comprises a plurality of segments (2a, 2b, 2c) inserted into each other and slidable with respect to each other, the segments (2a, 2b, 2c) having each a respective hole (3) for the passing through of a spindle (104) preset to grasp a core (106) of a reel (102), the holes (3) being coaxial and defining a central axis (A); the segments (2a, 2b, 2c) comprising each a respective perimeter wall (4a, 4b, 4c) developing parallel to the central axis (A); the actuator comprises a plurality of springs (9) placed inside perimeter walls (4b, 4c) and active onto said core (106) to withdraw it from said spindle (104).

Inventors:
COLOMBO LUIGI (IT)
FRIGGERI DANILO (IT)
Application Number:
PCT/IB2018/059123
Publication Date:
May 31, 2019
Filing Date:
November 20, 2018
Export Citation:
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Assignee:
RE S P A CONTROLLI IND (IT)
International Classes:
B65H49/32; B65H16/06; B65H75/18
Foreign References:
EP3153439A12017-04-12
US5123604A1992-06-23
US5820069A1998-10-13
JP2013032206A2013-02-14
US4121783A1978-10-24
Attorney, Agent or Firm:
GIRLANDO, Mario et al. (Piazza Armando Diaz 7, Milan, IT)
Download PDF:
Claims:
CLAIMS

1. A linear actuator (1) of a type connectable to an arm (101) of a movable arm unwinder (100) for reels (102); said actuator (1) comprising a plurality of segments (2a, 2b, 2c) inserted into each other and slidable with respect to each other, said segments (2a, 2b, 2c) having each a respective hole (3) for the passing through of a spindle (104) preset to grasp a core (106) of a reel (102), said holes (3) being coaxial and defining a central axis (A); said segments (2a, 2b, 2c) comprising each a respective perimeter wall (4a, 4b, 4c) developing parallel to said central axis (A), the segment (2c) closest to said central axis (A) being configured for resting on said core (106); characterized in that it comprises elastic means (8) placed inside said perimetric walls (4b, 4c) and active onto said core (106) to withdraw it from said spindle (104), said elastic means (8) comprising one or more groups (10) of springs (9), each group (10) being active between a pair of said segments (2a, 2b, 2c) and comprising two or more springs (9), the springs (9) of each group (10) being angularly evenly spaced with respect to the central axis (A).

2. The actuator (1) according to the previous claim, characterized in that the springs (9) of each group (10) are balanced along the central axis (A).

3. The actuator (1) according to the previous claim, characterized in that each group (10) comprises an even number of springs (9), the springs (9) of each group (10) being arranged in pairs symmetrically with respect to the central axis (A).

4. The actuator (1) according to any of the previous claims, characterized in that each segment (2a, 2b, 2c) includes a first abutting surface (13a) and/or a second abutting surface (13b), said abutting surfaces (13a, 13b) being transversal to said central axis (A), said springs (9) being arranged each between a first abutting surface (13 a) of one of said segments (2b, 2c) and a second abutting surface (13b) of another of said segments (2a, 2b).

5. The actuator (1) according to the previous claim, characterized in that it includes a plurality of seats (14) for said springs (9), each seat (14) being at least partially cut inside one of said perimetric walls (4b, 4c), said first abutting surfaces (13a) being defined inside said seats (14).

6. The actuator (1) according to the previous claim, characterized in that said second abutting surfaces (13b) are derived in proximity to said perimetric walls (4a, 4b) and face a corresponding seat (14) of another segment (2b, 2c).

7. The actuator (1) according to any of the previous claims, characterized in that it does not comprise any gasket between said segments (2a, 2b, 2c).

8. The actuator (1) according to any of the previous claims, characterized in that it comprises four segments (2a, 2b, 2c), the innermost segment (2c) including a rest zone (7) for getting in contact with the core (16) of said reel (102). 9. An actuation group for movable arm unwinders (100) for reels (102), comprising a spindle (104) coaxially attachable to a shaft (103); characterized in that it comprises at least one actuator (1) according to any of the previous claims coaxially attached to said spindle (104).

10. An unwinder (100) for reels (102) comprising a pair of arms (101) arranged vertically and movable so as to get closer to/move away from each other, a motor-driven shaft (103) arranged horizontally and connected to an upper end (lOla) of one of said arms (101); an actuation group according to the previous claim, said spindle (104) being coaxially secured to said shaft (103).

Description:
"Telescopic linear actuator of a type connectable to an arm of a movable arm unwinder”

DESCRIPTION

The present invention relates to a telescopic linear actuator of a type connectable to an arm of a movable arm unwinder. In particular, such actuator is used to unload reels from self-expanding spindles that are installed on movable arm unwinders. By way of mere example, the reels may be of paper, cardboard, corrugated cardboard and flexible laminates in general.

The use of self-expanding spindles installed at an end of each movable arm of the aforementioned unwinders is known in the prior art.

The operation of these known self-expanding spindles involves the radial expansion of blocks actuated by a supporting pin which is eccentric in shape and is integral with the bearing drive shaft of the movable arm unwinder.

Such blocks exit automatically from the self-expanding spindles upon the rotation of the supporting shaft of the unwinder, and they make it possible to retain and center a reel, and also to support its weight during rotation.

It should be noted that, for the purpose of effectively clamping the reel, these spindles exert a high radial force, in particular on the internal part of the reel, called the "core", around which the paper or the like is wound. As a result thereof, the core of the reel remains constrained to at least one self-expanding spindle during the operations to unload the reel, thus necessitating difficult manual interventions by the operators for its removal. These interventions, as well as being risky for the operators, very often cause damage to the core.

In order to overcome this drawback, devices for unloading reels are known in the prior art. An example of such devices is described in patent application EP 3 153 439 Al filed in the name of Renova S.r.l. This publication describes a telescopic linear actuator for movable ami unwinders, which comprises a first annular cylinder, provided with a respective cavity, and a second annular cylinder inserted into such cavity so that it can slide within the first cylinder. Even the second annular cylinder is provided with its own respective cavity. An annular piston is inserted inside the cavity of the second cylinder so that it can slide with respect to the second cylinder. Both the cylinders and the annular piston are provided with respective holes for the passage of a self-expanding spindle.

As is widely known in the prior art, the actuator described in the Renova patent application can also be pneumatically actuated. This type of actuation is dictated by the need, known in the relevant technical field, to exert forces of around 500 kg so as to be sure of actually being able to unload the reel from the spindle. Lower forces may not be sufficient, leaving the core of the reel trapped on the spindle and requiring once again the operator’s intervention.

A disadvantage of activating the actuator’s pneumatic system is that it entails a series of drawbacks, for example, the need to provide gaskets between one cylinder and another. It should also be noted that an actuator of this type requires a pneumatic circuit capable of supplying the air at the required pressure. This circuit requires, in order to be integrated into the unwinder, that the shaft on which the spindle is mounted is hollow. It follows therefrom that the pneumatic actuation, besides giving rise to considerable complications from a manufacturing point of view, also makes the installation of the actuator on an unwinder that has not been suitably arranged therefor impractical.

SUMMARY OF THE INVENTION In this context, the technical task underlying the present invention is to propose a linear actuator of a type that can be connected to a movable arm unwinder that overcomes the above-mentioned drawbacks of the prior art.

More specifically, the present invention aims to provide a linear actuator of a type that can be connected to a movable arm unwinder that is simpler to manufacture and, at the same time, able to guarantee with certainty the expulsion of the reel.

The present invention also aims to provide a linear actuator of a type that can be connected to a movable arm unwinder that can, when the same force is provided, be manufactured in a more compact version.

The specific technical task and the objectives that have been specified are substantially achieved by a linear actuator of a type that can be connected to an arm of a movable arm unwinder, including the technical characteristics described in one or more of the attached claims.

More specifically, an embodiment of the present invention relates to a linear actuator of a type which can be connected to an arm of a movable arm unwinder for reels. This actuator comprises a plurality of segments inserted one into the other that slide relative to one another.

Each segment respectively has a hole for the passage of a spindle preset to grasp the core of a reel. The holes of the segments are coaxial and define a central axis of the actuator.

Each segment has a respective perimeter wall, which develops parallel to the central axis.

The segment closest to the central axis is configured to rest on the core of the reel.

The actuator comprises elastic means placed inside the perimeter walls. This elastic means are active onto the reel core to withdraw it from the spindle. This actuator solves the technical problem, insofar as it combines the manufacturing approach of a telescopic mechanism to the movement given by the elastic means. As a result, it is possible to provide an actuator which, unlike the types of elastic actuators previously in use, is able to exert a force sufficient to eject the reel.

Furthermore, the actuator, in accordance with the invention, does not require large internal cavities, which are instead required in the actuator described in the above- mentioned Renova patent application, since it does not require the use of compressed air. As a result, the elastic means are much more compact with respect to the same force exerted than a pneumatic actuation, leading to a reduction in the size of the actuator when using the same specifications.

Advantageously, the linear actuator according to the invention does not require any type of gasket or seal.

Advantageously, the linear actuator according to the invention can be installed on any of the unwinders that are already on the market, since it does not need to be adapted to the motor shaft, that is to say it does not require said shaft to be drilled.

LIST OF FIGURES

Further characteristics and advantages of the present invention will become clearer from the indicative, and therefore non-limiting, description of a preferred but not exclusive embodiment of a linear actuator of a type that can be connected to an arm of a movable arm unwinder, as illustrated in the accompanying drawings in which:

Figure 1 is a top view of a linear actuator according to the present invention;

- Figures 2a and 2b are sectional side views along the plane K-K of the linear actuator in Figure 1, respectively in an extended and a retracted configuration; Figure 3 is a front view of the linear actuator in Figure 1 in the extended configuration;

- Figure 4 is a sectional view of the linear actuator in a configuration of Figure 3 along the plane I-I;

Figure 5 is a front view of the linear actuator in Figure 1 in the retracted configuration;

Figure 6 is a sectional view of the linear actuator in the configuration illustrated in Figure 5 along the plane H-H; and

- Figures 7a, 7b and 7c are schematic front views of a movable arm unwinder comprising the linear actuator in Figure 1, in the respective operating configurations.

DETAILED DESCRIPTION

With reference to the attached figures, 1 indicates a linear actuator according to the present invention. In particular, such actuator 1 is of a type connectable to an arm 101 of a movable arm unwinder 100 for reels 102.

With particular reference to Figures 7a-7c, the unwinder 100 comprises a pair of 101 arranged vertically. The arms 101 are movable so as to get closer/move away from each other, in particular driven by a motor 105.

The unwinder 100 comprises a shaft 103 arranged horizontally. Such shaft 103 is connected to an upper end 101a of one of the arms 101. Preferably, as shown in Figures 7a-7c, both arms 101 are provided with respective shafts 103. One of the shafts 103 is motorized in such a way as to unwind the reel 102.

A spindle 104 is coaxially secured to the shaft 103, and is preset to grasp the inside of a core 106 of said reel 102. The unwinder 100 preferably comprises a pair of spindles 104. The structure and functioning of the spindle 104 is already known to the person skilled in the art, and will not, therefore, be described in detail.

It should be noted that the spindle 104 illustrated in the attached figures is of an eccentric type, that is to say, it comprises a cam 107 inserted inside a main body 108. Jaws 109 protrude from the main body 108. When the cam 107 is made to rotate with respect to the main body 108 by the movement of the shaft 103, it pushes the jaws 109 outwards, grasping the core 106.

Preferably, both shafts 103 are provided with a spindle 104, so as to be able to grasp both ends of the reel 102.

The actuator 1 is coaxially secured to the spindle 104. In particular, in the case of an eccentric spindle 104, such as the one shown in the attached figures, the actuator 1 is connected both to the spindle 104 and to the shaft 103, in particular by means of bearings 110. It should be noted that the unwinder 100 shown in Figures 7a-7c comprises a pair of actuators 1, each coaxially connected to the respective spindle 104.

With reference to Figure 2a, the actuator 1 comprises a plurality of segments 2a,

2b, 2c. These segments 2 a, 2b, 2c are inserted into each other. Moreover, the segments 2a, 2b, 2c are slidable with respect to each other. Advantageously, this makes the actuator 1 telescopic.

According to the described embodiment, the actuator 1 comprises four segments 2a, 2b, 2c. The innermost segment 2c has a rest zone 7 for getting in contact with the core

106 of the reel 102.

The segments 2a, 2b, 2c each have a respective hole 3 for the passing through of said spindle 104. Such holes 3 are coaxially arranged, so that they can define a central axis “A”

The segments 2a, 2b, 2c each comprise a respective perimeter wall 4a, 4b, 4c, which develops parallel to the central axis "A". With particular reference to Figure 1, the perimeter walls 4a, 4b, 4c of the segments 2a, 2b, 2c are axially symmetric and, in particular, cylindrical. These perimeter walls 4a, 4b, 4c are substantially slidable being in contact to each other, even if they do not need to be airtight. In particular, there are no gaskets between the segments 2a, 2b, 2c.

With particular reference to Figures 2a and 2b, it should be noted that the segments 2a, 2b, 2c can be switched from an extended to a retracted configuration. More details will be provided later on in this description.

More in detail, segments 2a, 2b, 2c are divided into three types. Proceeding from outside the actuator 1 towards the central axis "A", an outer segment 2a is encountered, optionally one or more intermediate segments 2b and an inner segment 2c.

The outer segment 2a has the largest diameter of all the segments 2a, 2b, 2c. This inner segment 2a is secured to the shaft 103 of the unwinder 100. The above-mentioned bearings 110 allow a mutual rotation between the outer segment 2a and the cam 107 of the spindle 104, which allows the spindle 104 to be locked and unlocked.

The outer segment has a bottom 5a that is transverse, and in particular perpendicular, to the central axis "A". The bottom 5a is secured to the perimeter wall 4a of the outer segment 2a, in particular at a proximal end of the shaft 103. This bottom 5a is shaped as a disk, and in particular as a circular disk. The hole 3 which allows the passage of the spindle 104 is drilled into the bottom 5 a. The bearings 110 are connected to the outer segment 2a at the bottom 5a, in particular on the edge of the hole 3.

With regard to intermediate segments 2b, they are to be considered optional and variable in number and size. In the described embodiment, the actuator 1 comprises two intermediate segments 2b. It should be noted that the larger intermediate segment 2b is inserted in the outer segment 2a, while all the others are inserted in the intermediate segment 2b having a larger diameter.

Each intermediate segment 2b comprises a respective bottom 5b that is transverse, and in particular perpendicular, to the central axis "A". The bottom 5b is secured to the perimeter wall 4b of the respective intermediate segment 2b, in particular at a proximal end of the shaft 103, as shown, for example in figure 4. This bottom 5b is shaped as a disk, in particular as a circular disk. The hole 3 which allows the passage of the spindle 104 is drilled into the bottom 5b.

It should be noted that, as will be explained in more detail later on in this description, the bottom 5b of each intermediate segment 2b extends towards the central axis "A" at least for a radial distance equal to the width of the perimeter wall 4b, 4c of the segment 2b, 2c inserted inside it. In other words, the perimeter walls 4b, 4c slide closer/away from the bottom 4a, 4b of the segment 2a, 2b in which they are inserted. In other words, a projection of each perimeter wall 4b, 4c parallel to the central axis "C" is entirely contained in the bottom 5a, 5b of the segment 2a, 2b in which it is inserted.

With particular reference to Figure 4, it should be noted that, unlike the intermediate segments 2b and the outer segment 2a, the inner segment 2c does not comprise a bottom similar to that of the other segments 2a, 2b. On the contrary, the inner segment 2c comprises a closing wall 6, which is connected to the perimeter wall 4c at a distal end with respect to the shaft 103. This closing wall 6 is shaped as a disk, in particular as a circular disk. The hole 3 which allows the passage of the spindle 104 is drilled into the closing wall 6. The closing wall 6 is, in particular, placed in contact with the main body 108 of the spindle 104, and can slide on it along the central axis "A".

It should be noted that the inner segment 2c is configured to rest on the core 106 of the reel 102 and/or on the reel 102 itself, in particular at the closing wall 6. In other words, the above-mentioned rest zone 7 is defined on the closing wall 6, in particular at an outer surface thereof.

With particular reference to Figures 2a and 2b, it should be noted that the segments 2a, 2b, 2c can be switched from an extended configuration to a retracted configuration. More details will be provided later on in this description.

As shown in Figure 3, the intermediate 2b and inner 2c segments comprise a groove 11 formed on the respective perimeter wall 4b, 4c. The outer 2a and the intermediate segments 2b comprise a slider 12, placed in particular on the perimeter wall 4a, 4b and inserted in a corresponding groove 11. The grooves 11 and the corresponding sliders 12 are adapted to limit the stroke of the segments 2b, 2c while switching from the extended to the retracted configuration.

According to the invention, the actuator 1 comprises elastic means 8 located inside the perimeter walls 4a, 4b, 4c. These elastic means 8 are active onto the core 106 to withdraw it from the spindle 104.

In particular, the elastic means 8 consists in a plurality of springs 9. Each of the springs 9 is active between a pair of segments 2a, 2b, 2c.

More in detail, the elastic means 8 comprise one or more groups 10 of springs 9. Each group 10 is active between a pair of segments 2a, 2b, 2c. As shown in Figures 2a and 2b, the described embodiment of the invention comprises three groups 10 of springs 9. More generally, the elastic means 8 comprise a number of groups 10 less than one with respect to the number of the segments 2a, 2b, 2c. It should be noted that the springs 9 of each group 10 are balanced with respect to the central axis "A", that is to say they collectively exert a force directed along that axis.

More in detail, it should be noted that each group 10 comprises an even number of springs 9. The springs 9 of each group 10 are arranged in pairs symmetrically with respect to the central axis A. More specifically, the springs 9 of each group 10 are angularly evenly spaced with respect to the central axis“A”. In the described embodiment, each group 10 comprises six springs 9, however, in other embodiments, the number of springs 9 for each group 10 can be any number whatsoever. It is also possible that, in order to modulate the response given by the actuator 1 , each group 10 comprises a different number of springs 9.

To load the springs 9 and allow the release of the stored elastic energy, each segment 2a, 2b, 2c has a first abutting surface 13a and/or a second abutting surface 13b. Such abutting surfaces 13a, 13b are arranged transversal to the central axis“A”. The springs 9 are arranged between a first abutting surface l3a of one of the segments 2b, 2c and a second abutting surface 13b of another segment 2a, 2b.

More in detail, the actuator 1 has a plurality of seats 14 for the springs 9. Each seat 14 is at least partially cut inside one of the perimeter walls 4b, 4c. In particular, the seats 14 are cut inside the perimeter walls 4b, 4c of the intermediate segments 2b and of the inner segment 2c. The number of seats 14 is preferably equal to the number of springs 9, while their arrangement in the segments 2b, 2c is determined by the arrangement of the springs 9.

It should be noted that the above-mentioned first abutting surfaces 13a are defined inside the seats 14. In other words, only the intermediate segments 2b and the inner segment 2c are provided with the aforementioned first abutting surfaces 13 a.

As far as the second abutting surfaces 13b is concerned, they are preferably cut outside the seats 14, in proximity of the perimeter walls 4a, 4b. The second abutting surfaces 13b face a corresponding seat 14 of another segment 2b, 2c. In particular, the second abutting surfaces 13b are cut inside a cavity 15 located on the bottom wall 4a, 4b of the outer segment 2a and the intermediate segments 2b.

The actuator 1 functions as follows. When the reel 102 is loaded onto the unwinder 100, as shown in Figure 7b, it compresses the actuator 1. The segments 2a, 2b, 2c switch to a retracted configuration, compressing the springs 9. The motor 105 thus provides the energy that is stored in the elastic means 8. When the reel 102 is unloaded, as shown in Figure 7c, the arms 101 move away, the spindle 104 releases its grip on the core 106 and the energy previously stored in the elastic means 8, in particular in the springs 9, is released. The core 106 is then pushed, withdrawing the spindle 104.