Patent Publication Number: US-2022212209-A1

Title: Application nozzle

Description:
The invention relates to an application nozzle for applying a viscous material to workpieces, in accordance with the preamble of claim  1 . 
     Such application nozzles, also called flat-stream nozzles, serve for producing a wide spray jet, for example for applying a varnish for seam sealing or an insulation material that must be applied flatly to a workpiece. Such application nozzles are used, in particular, for coating car body components in the automotive industry, but also for coating components of other devices, such as, for example, built-in appliances for kitchens. In order to obtain a wide spray jet, the application channel widens in a first spatial direction, toward the material outlet, in which direction the width of the application nozzle is measured, which width is generally many times greater (for example 5 to 10 times greater) than the thickness of the nozzle body, measured in a second spatial direction perpendicular to the first spatial direction. This can be accompanied, both in the case of the application nozzles according to the state of the art and in the case of the application nozzle according to the invention, by a narrowing of the application channel in the second spatial direction. The nozzle body is mounted on a nozzle holder through which a feed channel extends, by way of which channel the material is passed into the application channel. The nozzle body is releasably fixed in place on the nozzle holder, wherein the nozzle holder has two clamping plates, in the case of previously known application nozzles, which plates lie against side surfaces of the nozzle body that face away from one another, and hold the body clamped in place in an interstice that forms between them. In this regard, in the case of previously known application nozzles, one clamping plate is connected, in one piece, with the base body of the nozzle holder that has the feed channel, while the other clamping plate is releasably fixed in place on the plate and on the nozzle body. However, this simple structure causes a disadvantage: An edge is formed at the transition between the base body of the nozzle holder and the clamping plate configured in one piece with it, which edge always has a radius due to the one-piece configuration. At this edge, a corresponding edge of the nozzle body cannot be inserted with precise fit due to this radius, so that a leak can occur between the feed channel and the application channel. An application nozzle is known from DE 10 2016n 014 271 A1, which nozzle has a two-part apparatus as a holder. 
     It is therefore the task of the invention to further develop an application nozzle of the type stated initially, in such a manner that its tightness is improved. 
     This task is accomplished, according to the invention, by means of an application nozzle having the characteristics of claim  1 . Advantageous further developments of the invention are the object of the dependent claims. 
     The invention is based on the idea of being able to structure the edges that delimit the interstice between the clamping plates, which interstice is intended to hold the nozzle body, as edges that are as sharp as possible and have a small radius, by means of the configuration of the two clamping plates as separate components and their releasable fixation on the base body and on the nozzle body, so that the nozzle body can be well fitted between the clamping plates, and a great degree of tightness exists at the transition from the base body to the nozzle body. The tightness is even further improved if, in accordance with an advantageous further development, the side surfaces of the nozzle body are inclined at an acute angle relative to one another, proceeding from the base body, wherein this angle is preferably maximally 30° and, in particular, maximally 10°. In particular if the clamping surfaces of the clamping plates, which surfaces lie against the side surfaces, run toward one another at the same angle, proceeding from the base body, these surfaces press the base body against the nozzle body when the latter is being clamped in place. 
     It is advantageous if the side surfaces extend, in each instance, all the way to an end region, which projects out of the interstice between the two clamping parts and has the material outlet, at which region the thickness of the nozzle body increases. A greater thickness of the nozzle body in the region of the material outlet increases the stability of the latter, so that it is mechanically more resistant to mechanical stresses, such as during cleaning, for example. In particular, the end region can be configured as a step that projects out of the side surfaces on both sides. 
     It is advantageous if the clamping plates lie flatly against one of the side surfaces of the nozzle body with a clamping surface, in each instance. In this way a good clamping effect is achieved. Furthermore, it is preferred that the clamping plates each have a groove in which part of the base body is held. This facilitates positioning of the clamping plates with reference to the base body. It is practical if the clamping plates and the nozzle body are fixed in place on one another by means of at least one screw and/or at least one pin. This represents a particularly simple type of attachment. 
     The nozzle body is preferably produced from hard metal. In this regard, a hard metal is understood to be a metal-matrix composite material, in which the hard substances, present in particle form, are held together by means of a matrix composed of metal. Hard substances that can be used are, in particular, metal carbides or metal nitrides, such as tungsten carbide, titanium carbide, titanium nitride, niobium carbide, tantalum carbide or vanadium carbide, for example. It is true that hard metal is a more expensive material than metal. However, it is significantly stronger and more wear-resistant, in particular with regard to abrasive viscous media. 
     According to an advantageous further development of the invention, which also represents an independent inventive improvement as compared with the state of the art, the nozzle body has two nozzle plates that lie flatly against one another, between which at least a section of the application channel is situated. It is advantageous if the nozzle plates lie loosely against one another and are pressed against one another by means of the clamping plates. It is possible that one of the nozzle plates has a depression that forms the application channel, while the other nozzle plate is ground to be flat and merely covers the depression, thereby delimiting the application channel on one side. However, it is preferred for the two nozzle plates to have the same construction. In this regard, it is preferred that each of the nozzle plates, on the side facing the other nozzle plate, has a delimitation surface that delimits the application channel, at least in certain sections; a step that projects out of the delimitation surface, having a first contact surface that runs parallel to the delimitation surface and lies against the other nozzle plate, and a second contact surface that follows the delimitation surface in planar manner, against which the first contact surface of the other nozzle plate lies. This solution according to the invention, in accordance with the also independent claim  10 , offers the advantage that the nozzle body is easier to produce, in particular if it is made from hard metal. In this regard, it is preferred that the nozzle plates lie against one another at contact surfaces relative to which the second spatial direction extends transversely and preferably perpendicular. It is advantageous if the nozzle plates are each produced in one piece and preferably produced from hard metal. 
     Furthermore, it is preferred that the application channel has a first section that extends from the material inlet and is delimited by the clamping plates on two sides, and a second section that extends toward the material outlet and is enclosed all around by the nozzle body. In this regard, it is possible that the application channel widens in the first spatial direction only in its second section. However, it is preferred that the first section also widens in the first spatial direction, proceeding from the material inlet toward the second section. In particular if the second section is delimited by the steps on sides that lie opposite one another, the nozzle plates can simply be produced from hard-metal plates. In this regard, a cut-out for forming the first section of the application channel is cut out of the hard-metal plate by means of erosion or cutting, and subsequently the delimitation surface and the second contact surface are produced by means of grinding along an edge that delimits the step. In this regard, only the contact surfaces and the surfaces that delimit the application channel have to be ground, while grinding of the side surfaces of the nozzle body, which surfaces face one another, is not necessary. 
     It is possible that sealing takes place by means of sealing contact of the nozzle body on the nozzle holder. However, it is also possible that the first section and an end section of the feed channel that opens into the first section at the material inlet are lined, at least in part, by means of a sealing element that lies against the base body and against the clamping plates, so as to improve the sealing effect. In this regard, it is preferred that the sealing element is produced in one piece from a thermoplastic material, preferably from polyoxymethylene (POM) or polytetrafluoroethylene (PTFE). It is advantageous if the sealing element has an outlet gap that opens into the second section, the width of which, measured in the first spatial direction, is multiple times greater than its thickness measured in the second spatial direction. In this regard, it is practical if the width of the outlet gap is maximally twice as great as the thickness of the second section, measured in the second spatial direction, and it is preferably equal in size in the sense that it differs from the thickness of the second section by at most 10%. 
    
    
     
       In the following, the invention will be explained in greater detail using two exemplary embodiments shown schematically in the drawing. The figures show: 
         FIG. 1 a , 1 b    an application nozzle in accordance with a first exemplary embodiment, in two perspective views; 
         FIG. 2 a , 2 b    the application nozzle according to  FIG. 1 a , 1 b    in a front view and in a side view; 
         FIG. 3 a , 3 b    a section along the line A-A according to  FIG. 2 a    and along the line B-B according to  FIG. 2 b   , respectively; 
         FIGS. 4 a  to 4 c    a nozzle plate of the application nozzle according to  FIG. 1 a , 1 b    in a perspective view, in a side view, and in a front view, and 
         FIG. 5 a , 5 b    an application nozzle in accordance with a second exemplary embodiment in two sectional representations, corresponding to  FIG. 3 a   ,  3   b.    
     
    
    
     The application nozzle  10  shown in the drawing, in accordance with the first exemplary embodiment, has a nozzle body  12  through which an application channel  14  for viscous material extends from a material inlet  16  to a material outlet  18 . The nozzle body  12  is releasably mounted on a nozzle holder  20 , which has a base body  22  through which a feed channel  24  for the viscous material extends all the way to a feed opening  26 . The nozzle body  12  sits on a surface  28  of the base body  22 , in which surface the feed opening  26  is situated, wherein the feed opening  26  communicates with the material inlet  16  in such a manner that the feed channel  24  opens into the application channel  14  at the feed opening  26 . The nozzle holder  20  furthermore has two clamping plates  30 , the clamping surfaces  32  of which, facing one another, lie against side surfaces  34  of the nozzle body  12  that face away from one another, and hold the nozzle body  12  with a clamping effect in an interstice  36  between the clamping plates  30 . For fastening to the base body  22 , each of the clamping plates  30  has a groove  38  in which a part  40  of the base body  22  is held, in each instance, which part is delimited in an upward direction by the surface  28 . Screw openings  42  extend through the nozzle body  12  and the clamping plates  30 , through which openings screws are passed, using which screws the clamping plates  30  are braced against the nozzle body  12 , so that the clamping surfaces  32  are pressed against the side surfaces  34 . Further screws  43  fix the clamping plate  30 , which faces the viewer in  FIG. 1 a   , in place on the base body  22 , while furthermore a cylinder pin  45  is passed through the clamping plate  30 , which faces the viewer in  FIG. 1 a   , and the base body  22 , and engages into a dead-end bore in the clamping plate  30  that faces away from the viewer in  FIG. 1   a.    
     In a first spatial direction  44 , parallel to the side surfaces  34 , the nozzle body  12  has a width b that is significantly greater than its thickness d, which is measured in a second spatial direction  46  that stands perpendicular to the first spatial direction  44 . The application channel  14  has a first section  48  that extends from the material inlet  16  and is open toward the side surfaces  34  and is closed off on both sides, forming a seal, by means of the clamping surfaces  32 . The first section  48  is followed by a second section  50  of the application channel  14 , which section extends all the way to the material outlet  18 . Both sections  48 ,  50  of the application channel  14  widen toward the material outlet  18  in the first spatial direction  44 , as is particularly shown in  FIG. 3 a   . This widening takes place at a constant opening angle, starting almost from the material inlet  16 . In this way, a wide spray jet having a low thickness is achieved with the application nozzle  10  when applying a viscous material to a workpiece. The two side surfaces  34  furthermore do not run parallel to one another, but rather run toward one another at an acute angle of approximately 8°, proceeding from the base body  22 . The same holds true for the clamping surfaces  32 , which also run toward one another at an acute angle of approximately 8°, proceeding from the base body  22 . Bracing of the clamping plates  30  by means of the screws then pulls the nozzle body  12  in the direction toward the base body  22  and fixes it in place, lying against this body, so that the transition from the feed channel  24  to the application channel  14  is sealed off well. Due to the configuration of the nozzle holder  20  with three separate components (base body  22 , clamping plates  30 ), the edges of all components can be precisely ground, so that they can be precisely joined together with the nozzle body  12 . A thickened end region  52  of the nozzle body  12  projects upward out of the interstice  36 , facing away from the base body  22 . The material outlet  18  is situated in this end region  52 . 
     The nozzle body  12  is composed of two nozzle plates  54  that have the same construction, each of which is produced in one piece from hard metal ( FIGS. 4 a  to 4 c   ). Each of the nozzle plates  54  is produced from a plate-shaped blank composed of hard metal. In this regard, first a section  56  having an open edge and forming the material inlet  16  and the first section  48  of the application channel  14 , in part, is introduced into the blank by means of erosion or cutting. Then the blank is ground down along an edge  58 , on one side, so that a step  60  remains. The step  60  has a first contact surface  62 . The step  60  is followed by a delimitation surface  64  that runs parallel to the first contact surface  62  and delimits the second section  50  of the application channel  14  toward one side. The delimitation surface  64  is followed, finally, by a second contact surface  66  that is coplanar with the former. Two nozzle plates  44  that have the same construction are loosely laid against one another to form the nozzle body  12 , in that the first contact surface  62  of the one nozzle plate  54  lies flatly against the second contact surface  66  of the other nozzle plate  54 , and vice versa. The second section  50  of the application channel  14  is then situated between the two delimitation surfaces  64 . Fixation of the nozzle plates  54  on one another takes place by means of the clamping plates  30  and the screws. 
     The application nozzle  110  in accordance with the second exemplary embodiment ( FIG. 5 a , 5 b   ) differs from the application nozzle  10  in accordance with the first exemplary embodiment, aside from its size and geometry, only in one detail. For this reason, the same characteristics are provided with the same reference symbols in the drawing and will not be described separately. While in the case of the first exemplary embodiment, sealing of the application channel  14  and of the feed channel  24  takes place in the region of the feed opening  26 , by means of sealing contact of the nozzle plates  54 , the clamping plates  30 , and the base body  22  against one another, in the case of the second exemplary embodiment the first section  48  of the application channel, which, incidentally, has a constant width in the first spatial direction  44  here, also over its entire length, and an end section of the feed channel  24 , which opens into the first section  48 , are lined by means of a sealing element  70  composed of a thermoplastic material. The sealing element lies against the nozzle body  12 , the base body  22 , and the clamping plates  30  all around, and ensures improved sealing in this region. The sealing element  70  has an exit gap  72  that opens into the second section  50  of the application channel, the thickness of which gap, measured in the first spatial direction  44 , is approximately as great as the thickness of the application channel  14  defined by the distance between the delimitation surfaces  64 . 
     In summary, the following should be stated: The invention relates to an application nozzle  10  for applying a viscous material to workpieces, having a nozzle body  12  through which an application channel  14  extends from a material inlet  16  to a material outlet  18 , wherein the nozzle body  12  has a width b, in a first spatial direction  44 , that is greater than a thickness d measured in a second spatial direction  46  that runs perpendicular to the first spatial direction  44 , and wherein the application channel  14  widens toward the material outlet  18 , in the first spatial direction  44 ; and having a nozzle holder  20  that has a base body  22  and two clamping plates  30 , wherein a feed channel  24  for the viscous material extends through the base body  22 , which channel opens into the material inlet  16  at a feed opening  26 , and wherein the clamping plates  30  releasably fix the nozzle body  12  in place on the base body  22 , lying against side surfaces  34  of the nozzle body  12  that face away from one another. According to the invention, it is provided that the two clamping plates  30  are configured as separate components and are releasably fixed in place on the base body  22  and on the nozzle body  12 , and/or that the nozzle body  12  has two nozzle plates  54  that lie flatly against one another, between which plates at least one section  50  of the application channel  14  is situated.