Patent Application
20220041393
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 3153139 A1 by Renova S.r.l. 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.
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.
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:
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
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
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 show) 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
Referring to
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
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
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
Particularly referring to
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
In a second embodiment, as shown for example in
In order to be mounted to the ejector 1, the adapter 37 comprises a bearing 40. In the embodiment of
| Number | Date | Country | Kind |
|---|---|---|---|
| 102020000019768 | Aug 2020 | IT | national |
