EP3950549A1

EP3950549A1 - Pneumatic linear actuator of a type connectable to an arm of a movable arm unwinder

Info

Publication number: EP3950549A1
Application number: EP21189608.9A
Authority: EP
Inventors: Stefano Lazzarin; Danilo Friggieri
Original assignee: RE SpA
Current assignee: RE SpA
Priority date: 2020-08-07
Filing date: 2021-08-04
Publication date: 2022-02-09
Also published as: US20220041393A1; IT202000019768A1

Abstract

A pneumatic linear ejector (1) of the type attachable to an arm (101) of a movable arm unwinder (100) for reels (102); the ejector (1) comprising a plurality of segments (2a, 2b, 2c) nested one in the other and slidable over each other, each having a respective seat (3) for the passage and/or accommodation of a chuck (104) configured to grasp a core (106) of a reel (102), the seats (3) are coaxial and define a central axis (A); the first segment (2a) is defined by an annular cylinder (20) attachable to an unwinder (100) and having a base (21) adapted to face the unwinder (100); a closing portion (25) is fixed to the first segment (2a) and closes the seat (3), the closing portion (25) is configured to support the chuck (104).

Description

The present invention relates to a linear ejector of the type attachable to an arm of a movable arm unwinder. In particular, this ejector is of pneumatic type and is used when unloading reels from self-expanding chucks, mounted to movable arm unwinders. By way of example, the reels may be made of paper, cardboard, corrugated cardboard and flexible sheets in general.
The use of self-expanding chucks mounted to one end of each movable arm of the aforementioned unwinders is known in the art.
These known self-expanding chucks operate by radial expansion of expansion units actuated by an eccentric journal, which is rigidly joined to the supporting drive shaft of the movable arm unwinder.
These expansion units automatically protrude out of the self-expanding chucks as the supporting shaft of the unwinder is rotated and allow a reel to be retained and centered, and its weight to be supported during rotation.
It should be noted that, for effective clamping, these chucks exert a high radial force, namely on the internal part of the reel, known as "core", around which the paper or the like is wound. As a result, the core of the reel remains constrained to at least one self-expanding chuck during the unloading operations, which requires difficult manual actions by the operators for removal thereof. In addition to being hazardous to the operator, these actions often cause damage to the core.
In an attempt to obviate this drawback, reel unloading devices are known in the art. One example of such devices is disclosed in patent application EP 3153439 A1 by Renova S.r.1. This publication describes a telescopic linear actuator for movable arm unwinders, which comprises a first annular cylinder having a respective cavity, and a second annular cylinder inserted inside said cavity and able to slide relative to the first cylinder. The second annular cylinder also has a respective cavity. An annular piston is inserted in the cavity of the second cylinder to be able to slide relative to the second cylinder. Both the cylinders and the annular piston have respective holes for the passage of a self-expanding chuck.
It is well known in the art that the actuator as disclosed in the Renova application is also pneumatically operable. Pneumatic operation is required due to the need, as is well known in the art, to apply forces of about 500 kg to be sure of effectively unloading the reel from the chuck. Lower forces may not be sufficient and leave the core of the reel stuck on the chuck, thereby still requiring an action by the operator.
One drawback of the linear actuator as disclosed in the Renova application is that it requires the chuck to be compatible, specifically it requires the shaft to be machined. As a result, the actuator cannot be typically mounted to a machine that doesn't have one, or the actuator cannot be combined with a chuck from another manufacturer.

SUMMARY OF THE INVENTION

Therefore, the technical purpose of the present invention is to provide a pneumatic linear ejector of the type attachable to an arm of a movable arm unwinder that can obviate the above discussed prior art drawbacks.
Namely, one object of the present invention is to provide a pneumatic linear ejector of the type attachable to an arm of a movable arm unwinder, that can be adapted to any type of shaft without machining.
The aforementioned technical purpose and objects are substantially fulfilled by a pneumatic linear ejector of the type attachable to an arm of a movable arm unwinder, that comprises the technical features as disclosed in one or more of the accompanying claims.
In particular, one embodiment of present invention relates to a pneumatic linear ejector of the type attachable to an arm of a movable arm unwinder for reels. This ejector comprises a plurality of segments nested one in the other and slidable relative to each other. Each segment has a respective seat for the passage and/or accommodation of a chuck adapted to grasp a core of a reel.
The seats of the segments are coaxial and define a central axis. The first segment is defined by an annular cylinder having a base that can be attached to an unwinder.
The ejector comprises a closing portion fixed to the first segment and closing the seat. This closing portion is configured to support the chuck.
The above-described ejector solves the technical problem in that the provision of the closing portion allows the ejector to be mounted even to machines that do not have one. This is because the closing portion allows the ejector to directly interface with both the shaft and the chuck, without requiring any adaptation to these two components.

LIST OF FIGURES

Further features and advantages of the present invention will result more clearly from the illustrative, non-limiting description of a preferred, non-exclusive embodiment of a pneumatic linear ejector of the type attachable to an arm of a movable arm unwinder, as shown in the annexed drawings, in which:

Figure 1 is an exploded view of a first embodiment of a pneumatic linear ejector of the present invention;
Figure 2 is a perspective view of a detail of the ejector of Figure 1;
Figure 3 is a sectional side view of the ejector of Figures 1 and 2;
Figures 4a, 4b and 4c are sectional side views of a second embodiment of a pneumatic linear ejector of the present invention, in a retracted configuration, in an intermediate extended configuration and in a fully extended configuration, respectively;
Figure 5 is a cross sectional view of an adapter for a pneumatic linear ejector;
Figures 6a, 6b and 6c are schematic front views of a movable arm unwinder comprising the pneumatic linear ejector of Figure 1 in respective operating configurations.

DETAILED DESCRIPTION

Referring to the annexed figures, numeral 1 designates a linear ejector of the present invention. Specifically, this ejector 1 is of the type attachable to an arm 101 of a movable arm unwinder 100 for reels 102. More specifically, the ejector 1 is of the pneumatically operated type.
Particularly referring to Figures 6a-6c, the unwinder 100 comprises a pair of arms 101, which are vertically arranged. The arms 101 are movable away from and/or toward each other, in particular driven by a motor 105.
The unwinder 100 comprises a horizontally arranged shaft 103. This shaft 103 is connected to an upper end 101a of one of the arms 101. Preferably, as shown in Figures 6a-6c, both arms 101 have respective shafts 103. One of the shafts 103 is motorized to unwind the reel 102.
A chuck 104 is coaxially connected to the shaft 103 and is configured to internally grasp the core 106 of the aforementioned reel 102. The unwinder 100 preferably comprises a pair of chucks 104. The structure and operation of the chuck 104 are well known to the skilled person and will not be further described herein.
It should be noted that the chuck 104 as shown in the accompanying drawings is of eccentric type, which means that it comprises a cam (not shown) inserted inside a main body 108. Jaws 109 protrude out of the main body 108. As the cam is rotated relative to the main body 108 by the movement of the shaft 103, it pushes the jaws 109 outwards, thereby grasping the core 106.
Preferably, both shafts 103 have a chuck 104, allowing both ends of the reel 102 to be grasped.
The chuck 104 is connected to the shaft 103 via the ejector 1. Namely, in the case of an eccentric chuck 104 like that depicted in the accompanying drawings, the ejector 1 is fixed to the shaft 103 and rotates therewith. The chuck 104 is directly fixed to the ejector, in a manner that will be further explained hereinbelow. It should be noted that the unwinder 100 as shown in Figures 6a-6c comprises a pair of ejectors 1, each coaxially connected to its respective chuck 104.
Referring to Figure 1, the ejector 1 comprises a plurality of segments 2a, 2b, 2c. These segments 2a, 2b, 2c are nested one in the other. In addition, the segments 2a, 2b, 2c slide relative to each other.
As used herein, the segments 2a, 2b, 2c will be presented in their positioning order from the shaft 103 to the reel 102. As a result, the first segment 2a is fixed to the shaft 103, whereas the last segment 2c has an abutment area 7 for contact with a flange 111 of the head.
In the described embodiment, the ejector 1 comprises three segments 2a, 2b, 2c, with the last segment 2c being the third segment from the shaft 103. In alternative embodiments, not shown, the ejector 1 can have any number of segments 2a, 2b, 2c depending on the type of application and on the force to be applied to the core 106.
Particularly referring to Figures 4a-4c, it should be noted that the segments 2a, 2b, 2c can be alternated between an extended configuration and a retracted configuration under a pneumatic thrust. Namely, Figure 4a shows a retracted configuration of the ejector 1, Figure 4b shows an intermediate configuration, and Figure 4c shows an extended configuration.
The first segment 2a and the second segment 2b each have a respective seat 3 for the passage and/or accommodation of the aforementioned chuck 104. These seats 3 are arranged coaxially, thereby defining a center axis "A".
In detail, the first segment 2a is defined by an annular cylinder 20. Such annular cylinder 20 has a base 21 which, as mentioned above, can be directly fixed to the shaft 103.
More in detail, the annular cylinder 20 comprises a base 21 which is transverse, specifically perpendicular, to the center axis "A". An outer wall 22 and an inner wall 23 extend away from the base 21. The base 21 and the walls 22, 23 define a chamber 24 within which the second segment 2b slides.
Referring to Figure 1, the inner wall 23 of the annular cylinder 20 defines the seat 3. According to the present invention, a closing portion 25 is fixed to the inner wall 23, and extends transverse, in particular perpendicular to the inner wall 23. This closing portion 25 at least partially closes the seat 3 of the first segment 2a. Preferably, the closing portion 25 completely closes the seat 3, and is configured to support the chuck 104. Therefore, in operation the chuck 104 is fixed to the closing portion 25. The shaft 103 is also fixed to the closing portion 25.
For pneumatic actuation of the ejector 1, the first segment 2a has a first opening 27 on said inner wall 23. It should be noted that the first opening 27 is located between the closing portion 25 and the base 21 of the annular cylinder 20, allowing it to be connected with a corresponding opening (not shown) formed on the shaft 103. Preferably, the first segment 2a has a plurality of first openings 27, more preferably angularly equidistant from the center axis "A". This affords pneumatic supply to the ejector 1 via the shaft 103.
Optionally, as shown for example in Figures 4a-4c, the annular cylinder 20 may have a second opening 15. This second opening 15 is particularly formed on the outer wall 22. Further details about the function of the second opening 15 will be provided hereinbelow.
Particularly referring to Figure 1, it should be noted that the second segment 2b is defined by an annular piston 28 inserted in said annular cylinder 20. The annular piston 28 has an outer cylindrical surface 31, which surrounds an inner cylindrical surface 32. Both cylindrical surfaces 31, 32 are coaxial with the center axis "A". A bottom 34 is arranged transverse, in particular perpendicular, to the cylindrical surfaces 31, 32. The bottom 34 is located inside the chamber 24 of the annular cylinder 20. An outer surface 33 is arranged parallel to the bottom 34 and outside the chamber 24. The annular cylinder 30 has a pair of first seals 26, arranged on the cylindrical surfaces 31, 32, to allow it to slide inside the chamber 24 under the thrust of a fluid, preferably air.
In operation, when pressurized air is introduced into the chamber 24, the annular piston 28 extends away from the base 21 of the annular cylinder 20.
More in detail, it should be noted that the second segment 2b has a plurality of cylinders 29. Therefore, the last segment 2c is defined by a plurality of pistons 30, preferably having a cylindrical shape, each inserted in a respective cylinder 29. In particular, the cylinders 29 of the second segment 2b are in angularly equally spaced arrangement relative to the center axis "A". Such cylinders 29 are located between the cylindrical surfaces 31, 32 of the annular piston 28, and in particular are accessible from the outer surface 33. In the illustrated embodiments, the last segment 2c of the ejector 1 is defined by eight pistons 30. In alternative embodiments, not shown, any number of pistons may be provided.
For pneumatic actuation of the pistons 30 that compose the last segment 2c , the cylinders 29 of the second segment 2b are in fluid communication with the annular cylinder 20 of the first segment 2a. Each of the cylinders 29 has an open end 35, formed on the bottom 34 of the annular piston 28. Each of the pistons 30 has a respective second seal 36.
It should be noted that the last segment 2c is configured to abut a flange 111 of the head, namely at a free end 30a of the pistons 30. In other words, the aforementioned abutment area 7 is defined by the free ends 30a of all the pistons 30.
The present invention also relates to a kit comprising the ejector 1 and an adapter 37. This adapter 37 has the function of allowing the ejector 1 to be mounted even on shafts 103 that have no pneumatic supply. For this purpose, the adapter 37 has an annular cavity 17 which, in operation, may be supplied by a source of pressurized fluid, for example air. The annular cavity 17 is configured to be positioned outside the first segment 2a of the ejector 1, namely at the above discussed second opening 15 of the annular cylinder 20, to be able to pneumatically supply the annular cylinder 20 from the outside.
More in detail, the adapter 37 has an outer cylindrical wall 39, which remains stationary in operation. This outer cylindrical wall 39 can be connected to the pneumatic supply.
More in detail, the adapter 37 comprises a pair of sealing rings 38, which can be associated with the outer wall 22 of the annular cylinder 20. These sealing rings 38, with the outer cylindrical wall 39, define the aforementioned annular cavity 16. In a first embodiment of the invention, as shown for example in Figures 4a-4c, the adapter 37 does not comprise additional walls between the sealing rings 38 and the outer wall 22 of the annular cylinder 20.
In a second embodiment, as shown for example in Figure 5, the adapter 37 optionally comprises an inner cylindrical wall 41 which can be fixed to the annular cylinder 20, in particular to the outer wall 22. Here, the inner cylindrical wall of the adapter 37 rotates with the annular cylinder 20 driven by the shaft 103 and has at least one opening 42 that can be positioned at the aforementioned second opening 15 of the annular cylinder 20. Advantageously, this embodiment may be used with any pneumatic linear actuator or ejector, possibly other than the ejector 1, as long as the above discussed second opening 15 has been formed therein.
In order to be mounted to the ejector 1, the adapter 37 comprises a bearing 40. In the embodiment of Figure 4a-4c, the bearing 40 is arranged between the outer cylindrical wall 39 of the adapter 37 and the outer wall 22 of the annular cylinder 20. In the embodiment of Figure 5, the bearing 40 is arranged between the outer cylindrical wall 39 and the inner cylindrical wall 41 of the adapter 37.

Claims

A pneumatic linear ejector (1) of the type attachable to an arm (101) of a movable arm unwinder (100) for reels (102); said ejector (1) comprising a plurality of segments (2a, 2b, 2c) nested one in the other and slidable over each other, the first segment (2a) and the second segment (2b) having each a respective central seat (3) for the passage and/or accommodation of a chuck (104) configured to grasp a core (106) of a reel (102), said seats (3) being coaxial and defining a central axis (A); the first segment (2a) being defined by an annular cylinder (20) which is attachable to an unwinder (100) and having a base (21) adapted to face said unwinder (100); characterized in that it comprises a closing portion (25) fixed to the first segment (2a) and closing the seat (3), said closing portion (25) being configured to support said chuck (104).
An ejector (1) as claimed in the preceding claim, characterized in that said first segment (2a) has an inner wall (23) defining the seat (3), said closing portion (25) being connected to said inner wall (23).
An ejector (1) as claimed in the preceding claim, characterized in that said first segment (2a) comprises a first opening (27) located on said inner wall (23).
An ejector (1) as claimed in the preceding claim, characterized in that said opening (23) is arranged between said closing portion (25) and said base (21).
An ejector (1) as claimed in any of the preceding claims, characterized in that the second segment (2b) is defined by an annular piston (28) inserted in said annular cylinder (20), the second segment (2b) having a plurality of cylinders (29), the last segment (2c) being defined by a plurality of pistons (30) each inserted in a respective cylinder (29) of the second segment (2b).
An ejector (1) as claimed in the preceding claim, characterized in that the cylinders (29) of the second segment (2b) are angularly equally spaced with respect to said central axis (A).
An ejector (1) as claimed in claim 5 or 6, characterized in that the cylinders (29) of the second segment (2b) are in fluid communication with the annular cylinder (20) of the first segment (2a).
A kit comprising a linear ejector (1) of the type adapted to be connected to an arm (101) of a movable arm unwinder (100) as claimed in any of the preceding claims, characterized in that said annular cylinder (20) has an outer wall (22) having a second opening (15), said kit further comprising an adapter (37) having an annular cavity (16) adapted to be connected with a fluid source and to be positioned at said second opening (15) for introducing fluid into said annular cylinder (20)
A kit as claimed in the preceding claim, characterized in that said adapter (37) comprises a pair of sealing rings (38) which are adapted to be associated with the outer wall (22) of the annular cylinder (20).
A kit as claimed in claim 8 or 9, characterized in that said adapter (37) has an outer cylindrical wall (39) and optionally an inner cylindrical wall (41) adapted to be fixed to the annular cylinder (20) and has at least one opening (42) adapted to be placed at the second opening (15) of the annular cylinder (20). said adapter (37) comprising at least one bearing (40) adapted to be arranged between the outer cylindrical wall (39) of the adapter (37) and the outer wall (22) of the annular cylinder (20) or between the outer cylindrical wall (39) and the inner cylindrical wall (41) of the adapter (37).
An unwinder (100) for reels (102) comprising a pair of vertically arranged arms (101) adapted to move away from and/or toward each other, a horizontally arranged shaft (103) connected to an upper end (101a) of one of said arms (101); a chuck (104) coaxially connected to said shaft (103); characterized in that it comprises at least one ejector (1) as claimed in any of claims 1 to 7, said chuck (104) being fixed to the closing portion (25) of said ejector (1).