EP0713729A1

EP0713729A1 - Dispenser having angled nozzle configuration

Info

Publication number: EP0713729A1
Application number: EP95115912A
Authority: EP
Inventors: Paul Schmidt; Wesley C. Fort
Original assignee: Nordson Corp
Current assignee: Nordson Corp
Priority date: 1994-10-31
Filing date: 1995-10-10
Publication date: 1996-05-29
Also published as: CA2159952A1; AU3454895A; JPH08224523A; AU695072B2

Abstract

A dispenser (10) having one or more dispensing nozzles (50) used for applying beads of thermoplastic liquid, such as hot melt adhesive, onto a moving substrate (58). The nozzle or nozzles (50) do not contact the substrate (58) and are oriented at an angle relative to the direction of substrate movement (64). A range of angles for the nozzle or nozzles (50) which has been found to be beneficial, for example, in terms of producing a cleaner, more uniform bead upon activation of the dispenser (10) and producing less cut-off drool or stringing, is from about 10° to about 40° relative to a plane which is perpendicular to the direction of substrate movement (64). An angle of 20° has been found to be most beneficial under a wide range of operating pressures for thermoplastic hot melt adhesive. Modular alternative nozzle configurations are also disclosed for allowing the same dispenser body (10) to be oriented either horizontally or vertically while still maintaining the same advantageous nozzle angle relative to the substrate (58).

Description

Field of the Invention

The present invention generally relates to a method and apparatus for dispensing viscous liquid beads from nozzles which do not contact the intended substrate.

Background of the Invention

Apparatus for dispensing beads of viscous liquid, such as so-called "hot melt" thermoplastic liquid adhesive, are used in such applications as securing carton flaps or other paper products together or securing a backing sheet to a nonwoven layer of a hygienic article. In applications such as these, rows of closely spaced hot melt adhesive beads are applied in the appropriate areas of the substrate by a dispenser comprising a plurality of adjacent nozzles aligned together in parallel and spaced a short distance, such as 1/32" or 1/16", from the substrate. Problems with these dispensers have included occurrences of adhesive "drool" from the nozzles upon "cut-off" or deactivation of the dispenser as well as problems with substrate movement or disruption during the dispensing operation which may result in adhesive being thrown from the substrate or result in unwanted contact between the substrate and portions of the dispensing apparatus.
Cut-off drool is of particular concern when adhesive beads are being dispensed in an upward direction onto a substrate. Heretofore, the bead application plane has been oriented 90^o relative to the direction of substrate movement. In this situation, any drool or "stringing" of the adhesive which occurs upon deactivation of the dispenser often falls directly down onto the dispenser. This creates a maintenance problem as the cleaning of adhesive from the outside surfaces of many dispensers is difficult. Because hot melt adhesive dispensers are operated at elevated temperatures, any adhesive on the outside surfaces thereof will usually become hardened and charred in a short period of time. Additionally, these dispensers are often mounted with respect to surrounding machinery such that access for cleaning purposes is difficult. For these reasons, increased maintenance efforts are often required after dispensing adhesive beads in an upward direction.
Apparatus for dispensing a plurality of parallel adhesive beads have been used to produce so-called "sift-proof" packages. A sift-proof package has seals created by the dispensed adhesive beads which eliminate leakage past the secured flaps of the package. This sift-proof seal is often desirable or necessary in the packaging of powdered or granular product. Often, these products are consumer oriented products such as sugar, cereal, laundry detergent and dishwashing detergent. Cut-off drool and "stringing" of adhesive is of particular concern in such consumer oriented sift-proof applications since it is especially undesirable from the consumer's standpoint to have adhesive inadvertently drooled, dropped or otherwise applied to the inside of a package.
Further problems particular to sift-proof applications are experienced with unstable substrates during upward or downward firing of adhesive beads. Specifically, when applying beads of adhesive to the unfolded flaps of erected cartons, the force of the adhesive stream or streams may be strong enough to cause the flap to be pushed away from the dispenser and then rebound towards the dispenser. This often results in undesirable contact between the carton flap and the dispenser which tends to drag adhesive from the intended application area or wipe adhesive onto the dispenser or dispenser nozzles. This rapid movement of the flap may also cause adhesive to be thrown from the flap onto the dispenser or other areas in or on the carton. As mentioned above, upward firing of adhesive beads in a plane perpendicular to the direction of substrate movement will also often result in drooling adhesive falling directly down on the dispenser.
Finally, many bead dispensers using nozzles oriented at 90^· relative to the substrate tend to dispense beads of thermoplastic liquid material in a nonuniform manner or without a clean "cut-on" and "cut-off". In other words, at the very beginning of the bead, or at "cut-on", there may be an excess volume of liquid which produces a wider, tear drop shaped portion of the bead. At the very end of the bead, or at "cut-off", there may be a lesser amount of thermoplastic material than is desired thereby producing a narrower bead width or "stringing" of adhesive at this region of the bead. Such nonuniform beads may affect the quality of a seal, for example, by causing excess liquid to be squeezed out between two substrates when pressed together. Stringing of adhesive may cause lower quality seals or other maintenance related problems.
In view of the above problems in the art, there is a need for dispensing apparatus particularly suitable for applying hot-melt adhesive in a noncontacting manner while preventing cut-off drool and certain other problems posed by past nozzle configurations which fire in planes perpendicular to the direction of substrate movement.
It has thus been one object of the present invention to prevent cut-off drool and stringing of adhesive in intermittent noncontact dispensing operations while maintaining a relatively low cost for the dispenser.
It has been an another object of the invention to dispense beads of adhesive with cleaner "cut-on", that is, with a more uniform bead width along its length.
It has been another object of the invention to prevent undesirable substrate movement, such as carton flap movement, during a thermoplastic liquid bead dispensing.
It has been yet another object of the invention to reduce the effective downward force of thermoplastic liquid beads striking the surface of an unstable substrate, such as the extended flap of a carton.
It has been a further object of the invention to prevent rebounding of dispensed thermoplastic liquid from a substrate, such as a carton flap, and contaminating other nearby areas, such as other exposed areas in or on the carton or other areas in the vicinity of the dispensing operation.
It has been still a further object of the invention to provide for simple changeover between horizontally and vertically oriented dispensing gun modules.

Summary of the Invention

To these ends, the present invention contemplates a dispenser having at least one noncontacting, dispensing nozzle operatively disposed at an angle other than 90^· to the receiving substrate and in the direction of substrate movement. Mounting structure is provided in accordance with this invention such that the nozzle is angled acutely and in a direction toward the direction of substrate movement relative to a plane oriented perpendicular to the substrate and its path of movement. Accordingly, a method incorporating the principles of the present invention involves spacing a tip of the angled nozzle from the substrate and moving the substrate in a direction corresponding to the direction of the angled nozzle as thermoplastic liquid is dispensed onto the substrate. The angular orientation of the nozzle or nozzles is preferably within a range of approximately 10° to 40° relative to a plane which is perpendicular to the path or plane of substrate movement. The most beneficial angle in a given application will vary depending on such factors as dispensing pressure and liquid viscosity. However, a dispensing angle of approximately 20° has been found to be most acceptable under a wide range of dispensing pressures, such as between 150-1200 psi, during hot melt adhesive dispensing operations.
More specifically, a preferred embodiment of the present invention takes the form of an intermittent non-contact dispensing gun module which generally includes a dispenser body and one or more nozzles operatively connected to the dispenser body at an angle as described above. The dispenser body therefore serves to mount the nozzle or nozzles at a preferred angle as described above and also serves to intermittently supply thermoplastic liquid material, such as hot melt adhesive, to the nozzle or nozzles.
The dispenser body preferably includes a valve which is movable between open and closed positions to provide for intermittent dispensing of liquid from the nozzle or nozzles. One or more dispenser bodies may be connected to a heated manifold for supplying pressurized thermoplastic liquid and pressurized air to the dispenser body. Further mounting structure may also be attached to the manifold for mounting the dispenser body or bodies as well as the manifold adjacent to the substrate. In the preferred embodiments, such further mounting structure comprises brackets for attaching the necessary dispensers and manifolds to packaging machinery such that the angled nozzles are positioned closely adjacent, but spaced from extended carton flaps to be glued during a packaging operation.
Two alternative embodiments of nozzle assemblies are provided by the present invention to mate with a single dispensing gun module body. One nozzle assembly allows the module body to be horizontally oriented with respect to the substrate during use while the other nozzle assembly allows the module body to be oriented vertically during use. When attached to the module body, which is then oriented either horizontally or vertically as appropriate for each nozzle assembly, the nozzles of each nozzle assembly will be oriented within the preferred angular range of approximately 10^·-40^· as discussed above. These alternative nozzle assemblies lend modularity to the dispensing guns of the present invention in that the same module body may be used in either a horizontal or vertical orientation simply by substituting nozzle components.
The present invention, while useful and beneficial in many dispensing applications, is especially advantageous in sift-proof packaging operations. In this regard, a specific pattern of hot melt adhesive beads is typically applied to both the upper and lower flaps of a carton before the upper and lower flaps are respectively folded into closed and sealed positions. Therefore, at least one set of dispensing guns is used to dispense adhesive beads downwardly onto the relative upper carton flaps and at least one set of dispensing guns is used to fire beads of adhesive upwardly onto the relative lower carton flaps.
The present invention provides improvements in this application generally by providing uniform cut-on and cut-off of the dispensed adhesive beads. That is, beads are applied which do not have any pronounced variations in width or volume at the beginning or end thereof as the present invention provides for cleaner "cut-on" and "cut-off" of such beads. Cut-off drool and stringing of material at the end of a dispensing cycle is also minimized. It is believed that these benefits are obtained for similar reasons, i.e., with the angled configuration of the nozzles, adhesive tends to be dragged onto the substrate and away from the nozzle at the beginning and end of the dispensing cycle.
In addition, the invention provides benefits specific to sift-proof and other applications involving relatively unsupported or unstable substrates and with firing beads of thermoplastic liquid upwardly onto a substrate. In the former regard, for example, the major flaps of a carton extend from a fold line with the main body of the carton during a packaging operation. Thus, these flaps are relatively unsupported and unstable and the force of a glue bead, applied in a noncontacting manner, may tend to cause rapid flap movement. With the angled configuration of the nozzles in the present invention, however, the force of the beads is redirected and reduced to prevent undesirable flap movement even under the same conventional dispensing pressures. In regard to firing beads of adhesive upwardly onto the relative lower flaps of the carton, an advantageous redirection and reduction of force is not only realized but, since the beads are being fired at a forward angle relative to the direction of substrate movement, any dripping or drooling which might happen to occur generally causes adhesive to fall on the floor ahead of the dispenser and not onto the dispenser itself.
Further objects and advantages of the invention will become readily apparent to those of ordinary skill in the art upon review of the following detailed description taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

Fig. 1 is a side elevational view of a dispensing gun module constructed in accordance with the present invention and being partially fragmented to illustrate certain inner details of its nozzle assembly;
Fig. 2 is a cross sectional view of the Fig. 1 taken along line 2-2 thereof;
Fig. 3 is a perspective view showing a front portion of the dispensing gun module of Fig. 1 dispensing a plurality of hot melt adhesive beads onto a substrate such as a carton flap;
Fig. 4 is a top view of dispensing apparatus incorporating three dispensing gun modules constructed in accordance with the present invention and schematically illustrating the positioning of the guns with respect to the relative lower flaps of a carton for firing beads of adhesive upwardly in a sift-proof pattern;
Fig. 5 is a side elevational view of dispensing apparatus as shown in Fig. 4 but illustrating downward orientation of the nozzles for dispensing liquid thermoplastic material such as adhesive in a downward direction;
Fig. 6 is top view of a carton having a typical sift-proof pattern of adhesive beads applied to its relative upper flaps; and
Fig. 7 is a cross-sectional view of an alternative nozzle assembly to that shown in Fig. 1 for vertically orienting the dispensing gun module body.

Detailed Description of the Preferred Embodiments

Referring first to Fig. 1, one preferred embodiment of the invention is illustrated in the form of a horizontally oriented dispensing gun module 10 generally comprising a dispenser body 12 having a nozzle assembly 14 secured to one end and an actuator housing 16 secured at the other end. Actuator housing 16 is secured to dispenser body 12 by bolts 20, 22, only two of which are shown in the drawing and nozzle assembly 14 is likewise removably secured to body 12 by bolts 29, 31 (Fig. 3). Actuator housing 16 houses a compression coil spring (not shown) which normally actuates gun module 10 into a closed or "off" state in a known manner. Gun module 10 is pneumatically actuated into an open or "on" state also in a known manner. One gun module which includes actuation mechanisms such as these is disclosed in U.S. Patent No. 4,465,212, (the '212 patent) which is assigned to the assignee of the present invention. The disclosure of the '212 patent is expressly incorporated herein by reference.
Most of the elements of dispenser 10 concerning the actuation thereof are not shown in the drawings as these do not form part of the present invention. For these, the '212 patent may be relied upon as illustrative of one example of a pneumatically actuated, spring return mechanism which may be utilized in carrying out the present invention. It will further be appreciated that many other types of pneumatically or electrically actuated dispensers may be utilized in practicing the present invention.
Referring now to Figs. 1 and 2, nozzle assembly 14 includes a nozzle body 28 having a plug portion 30 which is received in a hole 32 in the end of dispenser body 12. An O-ring seal 34 surrounds plug portion 30 and provides a fluid tight seal between plug portion 30 and hole 32. Plug portion 30 includes a central adhesive passage 36 which receives a valve stem 38 as well as liquid thermoplastic adhesive under pressure from dispenser body 12. Valve stem 38 includes a ball or rounded valve member 40 at its outer end which seats against a valve seat 42 formed between adhesive passage 36 and a second, smaller diameter adhesive passage 44 in nozzle body 28.
Nozzle assembly 14 further comprises a nozzle plate 46 secured in a removable manner to nozzle body 28 by bolts 48, only one of which is shown in Fig. 1. Nozzle plate 46 has at least one nozzle 50 and preferably a plurality of nozzles 50 secured therein, such as by being press fit into respective holes in nozzle plate 46. In the embodiment shown in Figs. 1-3, nozzle plate 46 has six nozzles 50 for providing approximately a one inch wide path of thermoplastic adhesive beads 51 on substrate 58 (see Fig. 3). As specifically shown in Figs. 1 and 2, nozzles 50 communicate with respective adhesive passages 52 in nozzle plate 46. Adhesive passages 52 all communicate with a common slot 54 in nozzle body 28 when nozzle plate 46 is attached to nozzle body 28. Slot 54 receives thermoplastic liquid from a central passage 56 which connects to passage 44.
As illustrated in Fig. 1, all nozzles 50 are aligned parallel with one another and extend along axes 60 disposed at an angle α with respect to a vertical plane 62. Plane 62 is perpendicular to the direction of substrate movement which is indicated by arrow 64. In the first preferred embodiment shown in Fig. 1, dispensing gun 10 may be referred to as having a lengthwise dimension oriented along a horizontal axis 15 which is parallel to the path or plane of movement (indicated by arrow 64) of substrate 58. Angle α may be in the range of approximately 10° to approximately 40°, while an angle α of approximately 20° is most preferred as it has been found to be most beneficial under a wide range of hot melt adhesive dispensing pressures, e.g., in a range of about 150-1200 psi. Nozzles 50 extend outwardly from a chamfered or angled surface 66 of nozzle plate 46. The axis 60 of each nozzle 50 is preferably perpendicular to surface 66 as also shown best in Fig. 1. It will be appreciated that module 10 may be mounted with nozzles 50 directed downwardly as shown in Figs. 1 and 3 or upwardly depending on the application needs. In either case, the angle and directional orientation of nozzles 50 with respect to substrate 58, plane 62 and the direction 64 of substrate movement are as shown in Fig. 1.
Referring now to Figs. 4 and 5, the present invention is shown embodied in a gun assembly 70 used in so-called "sift-proof" packaging operations. More particularly, a gun assembly 70 is used for dispensing a specific pattern of adhesive beads on a substrate 58 which, in this case, is a carton having extended and substantially unsupported flaps as will be described further below. Gun assembly 70 includes a heated manifold 72, which may be conventional in all respects, for supplying both pressurized air and pressurized hot melt adhesive to a plurality of dispensing gun modules 74, 76, 78. Attached to the rear of manifold 72 are two clamp assemblies 80, 82 receiving a rod 84 which may be rigidly secured, as by welding, to packaging machinery or other stationary support structure. Each clamp assembly 80, 82 comprises a pair of clamp members 86, 88 secured together by two bolts 90, 92 which may be tightened down such that clamp members 86, 88 securely clamp rod 84 therebetween. Each dispensing gun module 74, 76, 78 is secured to manifold 72 by mounting bolts 94.
Dispensing gun modules 74, 76, 78 as shown in Fig. 4 are constructed essentially identically to the dispensing gun module 10 described in connection with Fig. 1-3. As is apparent from Fig. 4, the only difference between gun module 10 and gun modules 74, 76, 78 relates to their respective nozzle assemblies 96, 98, 100 which are designed to dispense adhesive beads in different numbers or, in other words, in patterns of different width. More specifically, nozzle assemblies 96, 98, 100 are formed in varying widths and/or with varying numbers of nozzles 50 for dispensing patterns of adhesive beads onto carton 58 in different widths as shown in Figs. 4 and 6. The dispensing gun assembly 70 shown in Fig. 4 is mounted with dispensing nozzles 50 of each gun module 74, 76, 78 mounted horizontally and facing in an upward direction. A standard sift-proof pattern of adhesive beads is shown in Fig. 4 as having just been dispensed onto the relative lower flaps of carton 58 which is moving in the direction of arrow 64. Fig. 6 fully illustrates this sift-proof pattern of adhesive beads on upwardly facing carton flaps. It will be appreciated that gun assembly 70 (Fig. 4) may be used to dispense beads onto upwardly facing carton flaps as shown in Fig. 6 simply by mounting gun assembly 70 with nozzles 50 facing downwardly. The upper and lower sides of carton 58 each include a pair of major flaps 102, 104 connected to the product receiving portion of carton 58 by respective fold lines 103, 105 and a pair of minor flaps 106, 108 connected to carton 58 by respective fold lines 107, 109.
In many sift-proof packaging applications, identical patterns of adhesive beads are dispensed onto both the upper and lower flaps of carton 58. As fully shown in Fig. 6, this sift-proof pattern consists of four adhesive bead sets 110, 112, 114, 116 with a set of beads being dispensed onto each end of each major flap 102, 104 and extending a short distance onto the corresponding side of each minor flap 106, 108. In addition, one major flap 104 includes a set of caulking beads 118 extending along substantially the full length of its outer edge. Thus, it will be appreciated that after this pattern of adhesive beads is dispensed onto flaps 102, 104, 106 and 108 as shown in Fig. 6, major flap 102 is folded over onto minor flaps 106, 108 and then major flap 104 is folded over onto the outside of major flap 102 to close and completely seal carton 58.
It will be appreciated that when downwardly oriented dispensing gun modules are dispensing beads sets 110, 112, 114 and 116, as shown in Fig. 6, any dripping, drooling or stringing of adhesive after applying a first set of beads would likely fall into the product receiving interior space 120 of carton 58. The unique angular configuration of nozzles 50, however, helps to prevent this undesirable occurrence. It is theorized that angling the nozzle in the direction of substrate movement allows the substrate to more effectively "pull" the adhesive from the nozzle at cut-on and cut-off.
Fig. 7 illustrates an alternative embodiment to the nozzle assembly 14 of gun module 10. In this regard, like reference numerals between Figs. 1-3 and Fig. 7 represent like structure while reference numerals in Fig. 7 having prime marks represent modified structure. Generally, nozzle assembly 14' allows the same dispenser body 12 to be used in either a horizontal orientation as shown in Figs. 1 and 3 or in a vertical orientation as shown in Fig. 7. In Fig. 7, dispenser body 12 and actuator housing 16 have been deleted since their constructions may remain identical in both the horizontal and vertical embodiments. Nozzle body 28' differs from nozzle body 28 only in minor respects to be discussed below. In a manner identical with nozzle body 28, nozzle body 28' includes a plug portion 30 having an O-ring seal 34 and a central thermoplastic liquid passage 36 ending at a valve seat 42. Valve seat 42 communicates with passages 44 and 56 and with slot 54 all as described in connection with Figs. 1 and 2.
In accordance with this alternative vertically oriented embodiment, a modified nozzle plate 46' is removably secured to nozzle body 28' by mounting bolts 48, only one of which is shown in Fig. 7. As with the first embodiment, one or more nozzles 50 are press fit into nozzle plate 46' and communicate with respective passages 52'. Passages 52' in turn communicate with slot 54 of nozzle body 28'. Each nozzle 50 is oriented to dispense thermoplastic liquid along an axis 60 which is oriented at an angle α with respect to plane 62 which is perpendicular to the path or direction of movement of substrate 58. Unlike the first embodiment, in which plane 62 is perpendicular to gun module axis 15, plane 62 is parallel to axis 15 of nozzle assembly 14' and gun module 10 (Fig. 1) in the alternative embodiment. Angle α is preferably within a range of approximately 10^· to approximately 40^· and most preferably about 20^· when dispensing hot melt adhesive at between 150-1200 psi. As with the first embodiment, each nozzle 50 is preferably oriented parallel with all other nozzles secured within nozzle plate 46'. Each nozzle 50 is oriented in a direction toward the direction 64 of substrate movement. Similar to the first embodiment, the axes 60 of nozzles 50 extend perpendicular to the nozzle plate surface 66' through which they extend. It will be appreciated that nozzle plate 46' provides a mounting orientation for nozzles 50 with respect to axis 15 of nozzle assembly 14' which is complimentary to that provided by nozzle 46 shown in Fig. 1 in order to present nozzles 50 at the same angle α with respect to the moving substrate 58 in each embodiment.
Fig. 7 further shows a flap or substrate stabilizer 130 and an insulating member disposed between stabilizer 130 and nozzle body 28'. These are the only two differences between nozzle body 28' and 28. Flap stabilizer 130 is conventional and serves to push substrate 58, which may be a carton flap, into a level position before adhesive beads are dispensed onto substrate 58 by nozzles 50. The dispensing gun modules shown in Figs. 1-6 also preferably include such flap stabilizers, however, these have not been shown in Figs. 1-6 for clarity purposes.
From the foregoing, it will be apparent that the only changeover necessary in switching a module 10 between horizontal and vertical orientations is to substitute nozzle plate 46 with nozzle plate 46' or vice versa. Stabilizer 130 may or may not have to be removed or replaced during the changeover, depending on the application. Alternatively, an entire nozzle assembly 14 or 14' may be removed and replaced with the other by way of bolts 29, 31 (Fig. 3).
In operation, each of the embodiments described above operates to dispense thermoplastic liquid, such as hot melt adhesive, in essentially the same manner. That is, referring generally to both Figs. 1 and 7, pressurized thermoplastic liquid adhesive travels through dispenser 10 and enters passage 36 in nozzle body 28 at a specific dispensing pressure. By way of a suitable conventional control system, valve stem 38 may be pneumatically actuated to lift off of valve seat 42 thereby allowing pressurized liquid hot melt adhesive to enter passages 44, 56 and slot 54. Then, depending on whether a horizontally or vertically oriented unit is being operated, liquid thermoplastic adhesive travels through passage 52 or 52' and nozzles 50 to be dispensed in bead form onto substrate 58 at a preferred angle α as substrate 58 moves in the direction of arrow 64. The same conventional control system may then be used to stop the flow of adhesive into passages 44, 56, 54 and 52 or 52' by exhausting the pressurized air used to open valve 40 and allowing the spring return in housing 16 (Fig. 1) to move valve 40 against valve seat 42.
By intermittently operating a plurality of dispensing gun modules, such as with manifold 72 shown in Figs. 4 and 5, a variety of bead patterns are possible. Such patterns may include the sift-proof adhesive bead patterns shown in Figs. 4 and 6, which are dispensed onto cartons moving through a packaging operation. Of course, gun module 10, having either nozzle assembly 14 or 14' attached thereto, may be mounted to dispense beads firing in either a downward or an upward direction. Also, as in the sift-proof application shown in Figs. 4-6, a plurality of upwardly and downwardly firing gun modules 10 may be utilized in one application. It will be appreciated that in both upward and downward firing operations, the angled nozzles 50 of both the horizontally and vertically mounted guns are mounted the same relative to substrate 58b and its movement. In this regard, Figs. 1 and 7 would merely need to be inverted to illustrate the upward firing orientation.
While preferred embodiments of the present invention have been described above in detail, Applicants do not intend to be bound by such details but intend to be bound only by the scope of the claims appended hereto.

Claims

Dispensing apparatus for noncontact dispensing of liquid thermoplastic beads onto a surface of a substrate moving relative to said dispensing apparatus, the apparatus comprising:
a dispenser body formed with an a liquid flow passage;
a nozzle operatively connected for fluid communication with an outlet of said liquid flow passage by a nozzle mounting, said nozzle and said dispenser body being operative to dispense said liquid thermoplastic material from said nozzle onto said surface of said substrate without contacting said surface; and
a dispenser mounting for mounting said dispenser body proximate said substrate, said nozzle mounting and said dispenser mounting combining to mount said nozzle at an acute angle with respect to a plane disposed perpendicularly to the direction of movement of said substrate.
The apparatus of claim 1 wherein said nozzle mounting includes a nozzle body connected to said dispenser body and a nozzle plate connected to said nozzle body, said nozzle plate having said nozzle connected thereto.
The apparatus of claim 2 wherein said nozzle body is removably connected to said dispenser body and said nozzle plate is removably secured to said nozzle body.
The apparatus of claim 3 wherein a plurality of nozzles are connected to said nozzle plate, each nozzle being in fluid communication with said liquid flow passage such that said plurality of nozzles extend along axes which are parallel to one another and disposed at said acute angle.
The apparatus of claim 1 wherein the dispenser body has a longitudinal axis; and
wherein the nozzle is connected by a nozzle mounting secured to said dispenser body and having a liquid flow passage in communication with said liquid flow passage of the dispenser body, said nozzle mounting including mounting means for mounting alternative nozzle configurations to said dispenser body, said mounting means being adapted to allow said dispenser body to be oriented with said longitudinal axis disposed alternatively in horizontal and vertical orientations while dispensing liquid from a corresponding one of said alternative nozzle configurations at the same angle relative to said substrate in both said horizontal and vertical orientations.
The apparatus of claim 5 wherein said nozzle mounting includes a nozzle body connected to said dispenser body having means disposed on said nozzle body for alternatively receiving first and second differently configured nozzle plates.
The apparatus of any of the above claims wherein said acute angle is in a range of approximately 10° to approximately 40°.
The apparatus of claim 7 wherein said acute angle is approximately 20°.
The apparatus of any of the above claims comprising a valve member disposed in said first liquid flow passage for controlling flow of said liquid thermoplastic material from said nozzle.
A method of dispensing thermoplastic liquid material in the form of a bead onto a substrate, the method comprising the steps of:
mounting at plurality of nozzles at an angle and in spaced relationship with respect to a surface of the substrate, said angle being acute relative to perpendicular to said substrate surface;
moving said substrate and said plurality of nozzles relative to one another such that said substrate moves in a direction corresponding to the direction of said angle; and,
dispensing a bead of thermoplastic liquid material from each said nozzle onto said substrate surface.