Patent Application
20220203672
The invention relates to applicator rollers for lacquer applications, with a conical roller core and with an interchangeable roller sleeve.
The invention further relates to the manufacture of such rollers, and to the industrial use of these rollers for lacquer applications, for example for applying varnishes on metal plates, and optionally also on wooden plates.
As such, applicator rollers with interchangeable roller sleeves are known from the prior art. Both cylindrical and conical roller cores and roller sleeves are known.
NL 7 707 402 and U.S. Pat. No. 4,144,812 (Strachan & Henshaw), for example, describe a printing roller with a roller core and a detachable printing sleeve, for use in rotogravure. The roller core, on the one hand, has a conical outer surface. This provides openings that serve as outlets for compressed air. The printing sleeve, on the other hand, has an inner surface which is also conical in shape and which fits snugly with the outer surface of the roller core.
This snug fit is caused by a preliminary tensioning of the printing sleeve relative to the roller core. In the relaxed state, the loose printing sleeve can therefore only be slid partially over the roller core, while it does cover the said openings. When compressed air is forced through the openings from the roller volume, the printing sleeve will expand radially. An air layer now allows the expanded printing sleeve to slide completely over the roller core. Then, when the pressure is lowered again, the roller sleeve shrinks, and tightly fixes to the roller core. The roller sleeve can only be removed when the air pressure is increased again.
Both NL 7 707 402 and U.S. Pat. No. 4,144,812 provide an internal air distribution block with radial ports to direct compressed air from a central air duct to the openings. However, the air distribution block is heavy, and it contributes significantly to the inertia of the roller. The production cost of this is also high.
DE 103 03 386 (Böttcher) further describes an applicator roller for applying varnishes to metal plates. It comprises a hollow roller core and a roller sleeve, both cylindrical in shape. With such a cylindrical design, it is necessary to provide additional air outlets near the end of the roller core. Only from this end can the loose roller sleeve be brought over the roller core. In addition, the inventors determined that the snug fit in cylindrical roller cores and sleeves is inadequate for the intended applications.
Furthermore, DE 198 46 677 (Windmöller & Hölscher) describes yet another cylindrical roller core. Internal tubing provides direct air conduction to openings through the supporting wall. However, it is very laborious to apply such internal tubing.
Some important features of applicator rollers with interchangeable roller sleeves are their simple but robust design, their durability, the clamping of the roller sleeve on the roller core, the production cost, the efficiency of the production process and the ease of use. Furthermore, the total mass and the moment of inertia are preferably as small as possible. After all, these are parts that must be able to rotate at a high frequency. As far as durability is concerned, it is also important that the roller core does not wear or tarnish only a limited amount. Among other things, no varnish must be able to penetrate between the roller core and the roller sleeve. Preferably, the roller sleeves can also be mounted and dismounted very smoothly, and preferably the air inlet is easily accessible.
In addition, the known designs do not sufficiently take into account mechanical strength and safety, in view of the greatly increased air pressure during mounting and dismounting of the roller sleeves.
The present invention seeks to find an optimal compromise between these sometimes-contrasting design criteria.
In a first aspect, the invention relates to a conical roller core according to claim 1. As an important advantage, the volume of the air distribution chamber is limited, via an internal wall portion that is provided in the roller volume. As a result, only a limited volume is placed under air pressure during use (e.g. for mounting/dismounting roller sleeves). So only a smaller pressure energy builds up. This has important safety advantages. There are also considerations regarding the total mass and the moment of inertia of the roller core. In particular, since the air distribution chamber extends annularly along the supporting wall, the moment of inertia can be reduced.
NL 7 707 402 and U.S. Pat. No. 4,144,812 do not provide an air distribution chamber which is annularly bounded by the supporting wall itself. Instead, a combination of radial air distribution channels is provided in an air distribution block. These channels are only connected to the supporting wall at the level of the openings. The production process is more cumbersome, and the moment of inertia of the roll core is higher. Finally, NL 7 707 402 and U.S. Pat. No. 4,144,812 do not provide an internal wall portion, inside the roll volume.
DE 103 03 386 is further away from the invention, since the roller core is not conical but cylindrical. Such applicator rollers are usually not suitable for the same applications as the present invention, because cylindrical roller cores allow only a lower preliminary tension in the printing sleeve. In the relaxed state, the (cylindrical) roller sleeve can only be slid a little bit over the end of the roller core. A first set of air vents is provided there. These are provided beyond the end flanges. They connect to an annular air distribution chamber located outside the internal roller volume. The moment of inertia will therefore be greater than with alternative cylindrical designs, with air distribution channels concealed in the end flanges themselves. Finally, DE 103 03 386 does not provide an air distribution chamber which is limited to a smaller partial volume of the internal roller volume.
DE 198 46 677 describes another cylindrical roller core and is therefore also further away from the invention. A first, preferred embodiment is provided with internal tubing. A second embodiment, which is disadvantageous according to DE 198 46 677, provides an annular internal wall portion.
In a further preferred embodiment (claim 4), the wall portion comprises an annular or disc-shaped, transverse intermediate flange. This intermediate flange defines the air distribution chamber. Since compressed air in the air distribution chamber will exert an outward pressure on the supporting wall, it is advantageous that the transverse intermediate flange acts as reinforcement there.
In a further preferred embodiment (claim 5), the air distribution chamber is enclosed between two transverse intermediate flanges. The volume of the air distribution chamber can thus be severely limited, the intermediate flanges additionally providing firmness to the supporting wall in an environment of the air distribution chamber.
They are preferably welded to the supporting wall. They are further preferably welded single-sidedly from the nearest end (claim 9). The latter provides an important production advantage.
The invention further provides an applicator roller (second aspect), a method according to claim 13, for mounting and dismounting roller sleeves (third aspect), and a method according to claim 15, for manufacturing a roller core (fourth aspect).
The invention relates to a roller core, an applicator roller, a method for mounting and dismounting interchangeable roller sleeves, and a method for manufacturing roller cores.
Unless otherwise defined, all terms used in the description of the invention, including technical and scientific terms, have the meaning as commonly understood by a person skilled in the art to which the invention pertains. For a better understanding of the description of the invention, the following terms are explained explicitly.
In this document, ‘a’ and ‘the’ refer to both the singular and the plural, unless the context presupposes otherwise. For example, ‘a segment’ means one or more segments.
When the term ‘around’ or ‘about’ is used in this document with a measurable quantity, a parameter, a duration or moment, and the like, then variations are meant of approx. 20% or less, preferably approx. 10% or less, more preferably approx. 5% or less, even more preferably approx. 1% or less, and even more preferably approx. 0.1% or less than and of the quoted value, insofar as such variations are applicable in the described invention. However, it must be understood that the value of a quantity used where the term ‘about’ or ‘around’ is used, is itself specifically disclosed.
The terms ‘comprise’, ‘comprising’, ‘consist of’, ‘consisting of’, ‘provided with’, ‘have’, ‘having’, ‘include’, ‘including’, ‘contain’, ‘containing’ are synonyms and are inclusive or open terms that indicate the presence of what follows, and which do not exclude or prevent the presence of other components, characteristics, elements, members, steps, as known from or disclosed in the prior art.
Quoting numerical intervals by endpoints includes all integers, fractions and/or real numbers between the endpoints, these endpoints included.
In a first aspect, the invention relates to a roller core comprising a tubular supporting wall with an outer surface extending conically widening, from a narrower end to a wider end, which roller core is provided at both ends with a transverse end flange for bearing mounting via a shaft or journal, which roller core further provides an air inlet adapted for supplying compressed air to an internal air distribution chamber communicating with two or more outward air outlets through the supporting wall, and which roller core is thereby adapted to receive an interchangeable roller sleeve that can be stretched under air pressure around the supporting wall,
In particular, the roller core comprises at least one internal wall portion, which wall portion is positioned in the internal roller volume, and which wall portion further limits the air distribution chamber to a smaller, airtight sealed partial volume of the internal roller volume.
Together with a matching roller sleeve, such a roller core can be combined into an applicator roller. Preferably, this applicator roller is specially adapted for industrial coating of flat and/or curved surfaces. A possible application is the varnishing of metal tin material in the metal packaging industry. In such applications, high pressure is often applied to the applicator roller. Preferably, the roller core can therefore withstand relatively high line loads (e.g. 30 kg/cm or more). However, the invention is not limited to this.
A number of possible embodiments are shown in more detail in the figures and described in more detail in the description of the figures.
In any case, the first important feature is that the roller core does not provide a heavy internal block—unlike NL 7 707 402—to form separate air channels that conduct compressed air up to the air outlets. This saves on total mass and moment of inertia. Rather, the roller core forms an air distribution chamber which is bounded by the supporting wall itself. The air distribution chamber therefore automatically connects to all air outlets grouped there in an annular fashion. In general, the moment of inertia of a design can be limited by avoiding mass at a greater distance from a central axis of rotation in that object. It is therefore advantageous for the roller core that the structure of the supporting wall itself is used to delimit the air distribution chamber in an annular manner, at the level of the air outlets. The compressed air introduced can then, for example, spread annularly along the inner surface of the supporting wall. No additional structure is provided to guide air up to the air outlets. Preferably, the air outlets start directly from the air distribution chamber, through the tubular supporting wall.
Secondly, applicator rollers for industrial lacquering applications are usually a lot larger than applicator rollers for use in rotogravure flexo printing. In particular, the internal roller volume is therefore larger. When such a complete roller volume is brought under air pressure—as is the case with DE 103 03 386, a large pressure energy will build up therein. This can lead to dangerous situations. It is generally recognised in pneumatic technology that special safety measures must be taken at a maximum pressure energy of 200 bar·L or higher. On the other hand, a maximum pressure energy of 50 bar·L or lower can be considered harmless. See, for example, the European Pressure Equipment Directive (2014/68/EU). In any case, it is advantageous that the volume of the air distribution chamber is limited via one or more internal wall portions. In addition, the air distribution chamber only occupies a smaller partial volume that can come under air pressure. The total pressure energy built up is lower. 1 bar is 105 Pascal.
The ‘(internal) roller volume’, as mentioned herein, refers to the reference volume that extends within the tubular supporting wall and between the end flanges. Only a smaller part of the roller volume is occupied by the air distribution chamber. Preferably, the roller volume is divided by means of at least one internal wall portion into the air distribution chamber and at least one further chamber.
Throughout this document there is also mention of ‘air outlets’, ‘compressed air’ and ‘air pressure’. Naturally, the invention is not limited to the use of one specific type of gas or gas mixture. Preferably, the air outlets extend radially through the tubular supporting wall at a specified distance from the narrower end. Preferably, this distance is at least 20% and at most 80% of the total length of the roller core, more preferably more than 20%, more preferably less than 80%, more preferably less than 70%, more preferably less than 60%, for example about 30%, about 40% or about 50% of the total length. The diameter of the air outlets is preferably between 0.5 and 5.0 mm. The number of air outlets is preferably between two and twelve. Preferably, these air outlets are uniformly distributed around the circumference. According to a non-exhaustive example, these are six air outlets which are grouped in an annular fashion and which are distributed uniformly over the circumference. The air outlets extend radially through the supporting wall.
Above, it is further specified that the roller core has a transverse end flange at both ends, for bearing mounting via a shaft or journal. It may be a shaft part (e.g. a journal) that is attached to such an end flange (e.g. by welding or screwing), or that is formed in one piece together with the end flange. In the latter case, this is referred to as, for example, a monoblock end flange+journal. However, the invention is not limited to any of these.
According to a further or alternative embodiment, the conicity of the outer surface of the supporting wall is between 0.20 mm/m and 0.50 mm/m. The ‘conicity’ refers to the diameter deviation of the outer surface of the supporting wall, over a certain length of the supporting wall. More preferably, the conicity is between 0.20 mm/m and 0.35 mm/m. For example, the conicity is about 0.25 mm/m, about 0.30 mm/m or about 0.35 mm/m.
According to a further or alternative embodiment, the diameter of the roller core is between 150 mm and 450 mm. The length is preferably between 1000 mm and 4000 mm.
The roller core is preferably made of metal, for example aluminium or steel. The roller core preferably further comprises aluminium, in view of the lower density of this material.
The roller sleeve, on the other hand, is preferably made in two layers. The roller sleeve therein comprises a roller sleeve carrier which is provided on the outside with a roller sleeve covering. For example, the roller sleeve carrier comprises a fibre-reinforced plastic. A suitable fibre material comprises glass fibre, aramid fibre and/or carbon fibre. A suitable plastic is based on a vinyl ester resin, a polyester resin or an epoxy resin. The roller sleeve covering may comprise a polyurethane, an isoprene isobutylene copolymer, a nitrile butadiene rubber, a chloroprene, an EPDM, a chlorosulfone rubber, a polyester polymer, silicone, a fluorocarbon elastomer or a rubber. Preferably, the roller sleeve covering comprises a polyurethane. Such roller sleeves are known to those skilled in the art.
According to a possible embodiment, the roller sleeve has a thickness between 1 mm and 5 mm. The thickness of the roller sleeve is preferably more than 1 mm, more preferably more than 2 mm. The thickness of the roller sleeve is preferably less than 5 mm, more preferably less than 4 mm. The thickness of the roller sleeve is preferably between 2 mm and 4 mm.
Optionally, the roller core provides an annular end stop for roller sleeves at one of either end. The end stop optionally provides for this purpose a transversely stepped, annular outer surface against which a flat end edge of the roller sleeve can abut. As an alternative, the end stop provides for this purpose an obliquely stepped, annular outer surface against which a chamfered end edge of the roller sleeve can abut. With such a design, the roller sleeve and roller core are matched to one another.
In a further or alternative embodiment, the air distribution chamber is annular or cylindrical. Both allow a circular distribution of compressed air over the air outlets along an inner side of the supporting wall. An annular chamber leaves the central axis of the roller core free. With the necessary adjustments, such a design can be compatible with both a through-shaft and with two separate shaft journals.
In a further or alternative embodiment, the air distribution chamber is limited to a partial volume in which at a pressure of 7 bar only a pressure energy of at most 200 bar·L can develop, preferably at most 50 bar·L. The pressure energy can therein be considered harmless.
Firstly, the invention is not limited to a certain value for the air pressure. Preferably, however, the air pressure during use (i.e. when mounting and/or dismounting interchangeable roller sleeves) is between 3 bar and 12 bar. More preferably, the air pressure is around 6-7 bar. For compressed air, 6-7 bar air pressure is a common value.
According to a possible embodiment, the internal roller volume is at least 30 L. If the full roller volume were to serve as an air distribution chamber, a pressure energy of 210 bar·L would build up therein at 7 bars of compressed air. Such a pressure energy can be dangerous. Special provisions must therefore be made. For example, the design must be reinforced to be able to withstand these pressures. The present invention provides an opportunity to advantageously limit the air distribution chamber to a smaller partial volume, for example about 25 L or less. At a common pressure of about 7 bar, only a pressure energy of 175 bar·L will build up herein, so less than 200 bar·L.
In a further or alternative embodiment, said internal wall portion comprises an annular or disc-shaped transverse intermediate flange. This intermediate flange defines the air distribution chamber. Since compressed air in the air distribution chamber will exert an outward pressure on the supporting wall, it is advantageous that the transverse intermediate flange acts as reinforcement there.
In a further or alternative embodiment, the air distribution chamber is enclosed between two transverse intermediate flanges. Such intermediate flanges can be positioned anywhere—preferably at 20-80% of the total roller length, measured from the narrower end. This does not affect the volume of the air distribution chamber itself.
In a further or alternative embodiment, at least one of the intermediate flanges comprises a spacer. This is advantageous during production, since the second intermediate flange can be arranged against the first (e.g. already attached) intermediate flange. Thus, in one possible embodiment, these are two separate intermediate flanges, which are arranged close to or against each other, and which are thus attached, within the supporting wall. The air distribution chamber is enclosed between them. Alternatively, it is a first intermediate flange, a spacer and a second intermediate flange which are formed in one piece (i.e. ‘monoblock’). This whole can then also be fixed within the supporting wall, for example via welded joints and/or via thermal clamping. Firstly, the invention is not limited to any of these attachment methods.
Preferably, the air distribution chamber is enclosed between a first and a second transverse intermediate flange separated by a spacer.
In a further or alternative embodiment, the spacer is provided centrally, the air distribution chamber extending annularly around the spacer. The air distribution chamber thus extends annularly, between the spacer and the inner surface of the supporting wall. Preferably, the annular air distribution chamber in cross section (i.e. transverse to a section of the ring shape) is larger than the cross section of the individual air outlets. This ensures a sufficiently even distribution of the air.
In a further or alternative embodiment, said intermediate flange or intermediate flanges are welded to the supporting wall. As an advantage, a welded connection always results in a gastight connection between the connected parts. However, the invention is not limited to welded joints. Alternatively, the intermediate flange or intermediate flanges are clamped (and preferably gastight) within the supporting wall, e.g. via thermal clamping after heating the supporting wall. Firstly, the invention is not limited to any of these.
In a further or alternative embodiment, said intermediate flange or intermediate flanges are only welded single-sidedly. For example, this concerns two separate intermediate flanges positioned closer to one end and welded sequentially (and only single-sidedly) from this nearest end. See also the non-limiting embodiment of
In a further or alternative embodiment, the air inlet is positioned non-centrally at one of the two end flanges. Optionally, such a non-central design is balanced by placing balancing weights. With a non-central placement of the air intake, the air inlet (and the further air distribution system) is essentially separate from the bearing. This has advantages during production, as described in the figures. In addition, a non-centrally positioned air inlet is still easily accessible. An air inlet passing through a shaft or journal, on the other hand, can weaken this shaft or journal.
According to an alternative embodiment, however, the air inlet is centrally positioned. The air inlet therein runs centrally through a shaft or journal, into the air distribution chamber.
Optionally, the roller core is further equipped with internal tubing to direct compressed air from the (centrally or non-centrally positioned) air inlet to the air distribution chamber.
In a second aspect, the invention further provides an applicator roller comprising a roller core and a roller sleeve. In particular, the roller core is in accordance with what has been described above. The same features and advantages can thus be reiterated in this regard.
In a third aspect, the invention provides a further method for mounting a roller sleeve, over a roller core, and/or for dismounting a roller sleeve, from a roller core, wherein the roller core is in accordance with what has been described above. The method comprises the steps of: (i) introducing compressed air, from the air inlet to the air distribution chamber, and (ii) sliding the roller sleeve over the roller core, under air pressure from air outlets. Preferably, the compressed air introduced can spread at least over the air distribution chamber, along an inner side of the supporting wall.
In a further or alternative embodiment, a pressure energy of at most 200 bar·L, preferably at most 50 bar·L., develops in the air distribution chamber. This has safety advantages. In the most preferred embodiment, the partial volume occupied by the air distribution chamber (and possibly internal tubing) is so small that only negligible pressure energy can build up therein, for example a maximum of 5 bar·L at 6-7 bar air pressure.
In a fourth aspect, the invention provides a further method for manufacturing the above-described roller core. The same features and advantages can be reiterated in this regard. The method comprises welding at least one internal wall portion to the supporting wall and/or to at least one of the two end flanges. In a possible embodiment, the internal wall portion comprises at least one transverse intermediate flange (annular or disc-shaped) which is welded single-sidedly to the supporting wall, from the nearest end.
In what follows, the invention is described by way of non-limiting examples and figures illustrating the invention, and which are not intended to and should not be interpreted as limiting the scope of the invention.
At each end 5, 6 the roller core 2 is still equipped with an end flange 7, 7′. These are each provided with shaft holes 9, 9′ for attaching two separate axle journals 8, 8′ (not shown). Both a permanent attachment (e.g. via a welded joint) and a non-permanent attachment (e.g. via a screwed joint of a shaft flange 10 in the fixing holes 11—see
The roller core 2 is further provided with another air inlet 15 for the input of compressed air. The air inlet 15 is positioned non-centrally at an end flange 7, next to the shaft hole 9. With such a separate air inlet 15 (i.e., not integrated in a shaft or journal 8), the execution of the journal 8 and bearings is separate from the air inlet 15. It is therefore possible to produce the air inlet 15 (and possibly the complete air distribution system) of two roller cores 2 with a different type of bearing, largely in parallel, via the same or similar production steps. This contributes to the efficiency of production. As can also be seen in
Compressed air can now be guided from the non-central air inlet 15 into an annular air distribution chamber 17. This air distribution chamber 17 covers only a smaller partial volume, located within the internal roller volume 25 of the hollow roller core 2. The air distribution chamber 17 is namely enclosed between two transverse intermediate flanges 27, 27′. The first intermediate flange 27 is mainly disc-shaped, the second intermediate flange 27′ is mainly annular. For the conduction of compressed air, the roller core 2 provides an internal air hose 16. The air hose 16 runs parallel to the central axis 26, from the air inlet 15 to near the air distribution chamber 17. Optionally, the air hose 16 is connected to a connection channel 32 that is exhausted in an end flange 27 (see
The intermediate flanges 27, 27′ are welded on the inner surface 20 of the tubular supporting wall 4 (see
Finally, the air distribution chamber 17 is still annularly enclosed by the inner surface 20′ of the tubular supporting wall 4. The supporting wall 4 further has as its main function that it supports the roller sleeve 3. With such a double function (i.e. Also bounding the air distribution chamber 17) savings are made on material and design complexity. The total mass and the moment of inertia are lower.
Optionally, at least one intermediate flange 27′ provides another central opening (see
The roller core 2 now provides two or more outward air outlets 31. These extend from the air distribution chamber 17, through the supporting wall 4. Compressed air can easily be divided annularly over these air outlets 31 via the air distribution chamber 17.
The roller core 2 shown is adapted for use in applicator rollers 1 for industrial lacquering applications. In particular, the roller core 2 is suitable for receiving an interchangeable roller sleeve 3 (not shown). In addition, the inner surface 22 of the roller sleeve 3 can be stretched around the outer surface 19 of the roller core 2 under air pressure. Fitting an interchangeable roller sleeve 3 is schematically illustrated in
An important feature (see, for example, in
Compressed air brought into the air distribution chamber 17, will exert a radial outward pressure on the inner surface 20′ of the supporting wall 4. An advantage of the intermediate flanges 27, 27′ is that they increase mechanical strength locally. It is therefore not necessary to reinforce the supporting wall 4 as a whole.
In the embodiment of
In
It is important that compressed air within the air distribution chamber 17 will exert an outward pressure on the supporting wall 4. It is therefore advantageous that the roller core 2 is locally reinforced there, by means of the transverse intermediate flange 27. This allows the supporting wall 4 to be carried out with a smaller wall thickness. The weight and particularly the moment of inertia of the roller core 4 around the central axis 26 are therefore lower.
In
Another advantage of the embodiments according to
In a first step, the first intermediate flange 27 is connected to an air hose 16, at a connection channel 32 that is provided in the intermediate flange 27. The whole is then led into the supporting wall 4. The positioning (see
Furthermore, the first intermediate flange 27 provides a spacer 28 (see also the embodiment of
Between the above-mentioned steps, or afterwards, the two end flanges 7, 7′ and the air outlets 31 can also be added. The outer surface 19 of the supporting wall 4 must be very precisely formed. Preferably, that outer surface 19 is therefore only finalised in a last step. Optionally, the roller core 2 is still balanced.
The numbered elements in the figures are:
It is believed that the present invention is not limited to the embodiments described above and that some modifications or changes can be added to the examples and figures described without re-evaluating the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019/5319 | May 2019 | BE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/054607 | 5/15/2020 | WO | 00 |
