Patent Application
20090294014
The invention relates to a device for the controlled delivery of a viscous material through a nozzle, for applying or spraying on adhesive, in particular hot glue, for example. The present application claims the priority of the German utility model DE-U-20 2008 007 386.3 filed on 3 Jun. 2008.
Such devices are typically conceived for an automatically controlled, machine process, which is subject to a high processing speed. The devices must accordingly fulfill high requirements in regard to precision, functionality, durability, and freedom from maintenance, but also ease of maintenance.
Furthermore, such devices are typically equipped with a—pneumatic, for example—controller, which on one hand controls the quantity of the adhesive and/or hot glue delivered through the nozzle. On the other hand, however, it controls whether a continuous bead, and/or a continuous strand or an interrupted strand is to be applied or only spots are to be applied. The composition of the adhesive and/or hot glue, but also the controller are more preferably designed in such a way that, for example, upon punctual application the adhesive and/or hot glue spots are always equally large and do not form threads.
The applicant has put two series of application heads on the market under the names SX and AX, which already fulfill these stated requirements to a high degree. (See Robatech brochures “SX-Serie Spritzköpfe für Schmelzkleber [SX series spray heads for hot melt adhesives]”, printing April 2003 and “AX 100 Serie Spritzköpfe für Schmelzkleber [AX 100 series spray heads for hot melt adhesives]”, printing June 2004.)
For specific applications and under specific conditions, however, it has been shown that the requirements described above could desirably be fulfilled to an even greater extent.
In particular, it has proven to be disadvantageous that the ease of maintenance of the application heads has suffered because they heat up to approximately 180° C. Furthermore, it has proven that the nozzle has not provided constant results if it was subjected to a temperature-changing air draft, for example. Mechanical damage could also often occur to the nozzle if the product to be glued was warped or had irregularities, for example.
The solution was found in that the application heads have been provided according to the invention with a sheath which insulates and protects them. This sheath is simultaneously shaped according to the invention in such a way that it has at least two diametrically opposite webs enclosing the nozzle.
The webs or also a circular protrusion enclosing the nozzle may project beyond the nozzle or lie at the same height. Preferably, however, they project beyond the nozzle at a distance and are shaped as runners whose longitudinal direction corresponds to the direction in which the product to be glued and/or the application heads are moved past one another. The runners are preferably designed as ramps, i.e., rising and falling again in profile, to avoid hooking on the product sliding past.
In a preferred embodiment of the device according to the invention for applying heated adhesive and/or hot glue, the webs and/or the runners are adjustable in their height in relation to the nozzle. However, it may be desirable depending on the type of application or the type of material to be glued to situate the nozzle and the webs at the same height, or to have the nozzle project beyond the webs or vice versa to have the webs project beyond the nozzle in such a way that the glued product may contact the webs, but no longer the nozzle. This adjustability may be implemented easily in that the housing is provided with webs of different heights and they are mounted as needed. This selection of appropriately tall webs may be supported further by a selection of nozzles of different heights. This adjustability of the vertical distance between the nozzle and the webs may also be implemented, however, in that the fastening of the housing to the application head is adjustable. This may be performed using an oblong hole, for example. However, embodiments in which the webs themselves are arranged so that they are displaceable and fixable within a frame, are also conceivable.
The housing enclosing the application head according to the invention may comprise plastic. For example, halves molded in the injection-molding method from PEEK (polyetheretherketone), PEI (polyetherimide), PES (polyethersulfone), PSU (polysulfone), or PPS (polyphenylene sulfide) or also fiberglass-reinforced variants have proven to be advantageous and wear resistant, and may be assembled using screws, for example. The applicant has had good experience with a 40% fiberglass-reinforced polyphenylene sulfide resin from Chevron Phillips Chemical Company LP of The Woodlands, Tex. named Ryton® R-4.
Furthermore, the housing may have slots according to the invention, which are used on one hand for better handling ability and on the other hand provide a surface enlargement, which ensures better heat dissipation to the environment.
According to the invention, the housing sheathes between 75 and 95% of the lateral surface of the application head. These are preferably complete sheaths which only still leave the terminals and the nozzle exposed.
The housing has a slider, which, preferably provided with a catch or click closure, is manually displaceable in such a way that it releases an opening which allows a replacement or adjustment of the nozzle.
The nozzle itself preferably has an opening diameter of 0.5 to 5.0 mm, depending on the viscosity of the adhesive and/or hot glue used. However, the applied pressure is also decisive, which may be up to 200 bar. To guarantee a continuous flow of the adhesive and/or hot glue through the nozzle, a filter is preferably integrated in the device. Furthermore, the nozzle optionally has a heatable nozzle extension or a heatable nozzle attachment.
The device according to the invention preferably has a controller which causes a continuous strand or an interrupted strand or only spots to be applied. This controller may operate pneumatically, for example. The combination of applied pressure, the nozzle composition, the viscosity of the adhesive and/or hot glue, and the controller are the decisive influencing factors on the application behavior of the device. Ideally, it is as constant as possible, uniform, and does not form threads. To influence thread formation, but also the temperature behavior of the nozzle itself, an air nozzle may be provided which blows against the nozzle.
As already described, continuous or interrupted strands are also only spots may be applied. However, spraying may also be performed, in greatly varying forms, for example, in the form of a spiral or whorl.
Thermoplastics, PUR adhesives, sealants, or butyl come into consideration as adhesives and/or hot glue. They are heated to a temperature of up to 200° C., i.e., preferably supplied to the device already heated, but the device itself preferably also has a heatable supply hose.
The device according to the invention is preferably a modular component of a device system. Each individual device then has an identical fastening, for example, in the form of a shell closable using screws. This fastening may in turn be attached to a shared fastening device of the device system. This may be a rod, for example, which is enclosed by the shell. In this way, multiple individual devices and/or application heads may be arrayed arbitrarily on the rod and shifted depending on how many parallel strands are to be applied and at which intervals to one another. The shell is in turn preferably openable, so that an already fastened application head does not have to be pulled off of the rod to attach an additional application head. Easy replaceability and ability to place the individual devices and/or the application heads arbitrarily spaced are thus to be ensured according to the invention in any case. The individual parts of the device according to the invention and their fastenings are kept identical or even standardized for this purpose.
The following advantages are achieved in relation to known devices by a device according to the invention for applying adhesive and/or hot glue:
Further implementations of the invention are specified in the figures and in the dependent claims.
The list of reference numerals is part of the disclosure.
The invention is explained symbolically and for exemplary purposes in greater detail on the basis of figures.
The figures are described coherently and comprehensively. Identical reference numerals indicate identical components, reference numerals having different indices indicate functionally-identical or similar components.
In the figures
FIG. 1—shows the frontal view of a device according to the invention for applying heated adhesive and/or hot glue;
FIG. 2—shows a side view of the device according to the invention from
FIG. 3—shows a perspective view of the device according to the invention from the two preceding figures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2008 007 386.3 | Jun 2008 | DE | national |
