AU4275789A - Nozzle attachment for an adhesive spray gun - Google Patents

Description

1.25[4 1.8

MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU CF STANDARDS STANDARD REFERENCE MATERIAL 1010a (ANSI and ISD TEST CNART No. 21

(11) 42757/89

FORM 1 SPRUSON FERGUSON

COMMONWEALTH OF AUSTRALIA

PATENTS ACT 1952

APPLICATION FOR A STANDARD PATENT

Nordson Corporation, incorporated in Ohio, of 28601 Clemens Road, Westlake, Ohio 44145-1148, UNITED STATES OF AMERICA, hereby apply for the grant of a standard patent for an invention entitled:

Nozzle Attachment For An Adhesive Spray Gun

which is described in the accompanying complete specification.

Details of basic application(s):-

Basic Applic. No: Country: Application Date:

268,002 7 November 1988

The address for service is:-

Spruson Ferguson Patent Attorneys Level 33 St Martins Tower 31 Market Street Sydney New South Wales Australia

DATED this TENTH day of OCTOBER 1989

Nordson Corporation

Registered Patent Attorney

THE COMMISSIONER OF PATENTS OUR REF: 109271 S&F CODE: 59195

SO 10645 10/10/S9

5845/3

(11)42757/89

SPRUSON FERGUSON

COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952

DECLARATION INSUPPORT OF A CONVENTION APPLICATION FOR A PATENT

In support of the Convention Application made for a patent for an invention entitled: entitled' NOZZLE ATTACHMENT FOR AN ADHESIVE SPRAY GUN"

i

ii r I/ Moorhead Thomas L. Moorhead T.homa.s...

[full name of declarant(s)]

iI i:i; iiri of 30600 Salem Drive, Bay Village, Ohio, U.S.A.

[full address of declarant(s) not post office box]

ii

do solemnly and sincerely declare as follows:-

1. I am/-We-ae-e authorised by Nordson Corporation, the applicant for the i patent to make this declaration on its behalf. i 2. The basic application as defined by Section 141 of the Act was made in the United States of America on November 7, 1988 by Charles H. Scholl

j 3. Charles H. Scholl, of 3699 Hermitage Drive, Duluth, Georgia, U.S.A. the actual inventor of the invention and the facts upon which the is

i i;( applicant is entitled to make the application are as follows:

The said applicant is the assignee of the actual inventor.

i I 4. The basic application referred to in paragraph 2 of this Declaration was the first application made in a Convention country in respect of the invention'the subject of the application. j DECLARED at Westlake, this /5 day of September, 19 89 i Ohio, USA i NORDSON CORPORATION .1

i Signature of Declaran Thomas L. Moorhead TO: THE COMMISSIONER OF PATENTS Vice President-Law c AUSTRALIA Assistant Secretary

KRS/228P

(11)42757/89

LODGED -WITH THIS APPLIC-A.TION ARE UNSUITABLE. FOR R.EPRODUCTION AND MAY -BE INSP,.ECTED AT THE PATENT OFFICE ANCETE

(12) PATENT ABSTRACT (11) Document No. AU-A-42757/89 (19) AUSTRALIAN PATENT OFFICE

(54) Title NOZZLE ATTACHMENT FOR AN ADHESIVE SPRAY GUN International Patent Classification(s) 4 (51) B05C 005/04 B05B 007/10 (21) Application No. 42757/89 (22) Application Date 10.10.89 Priority Data (31) Number (32) Date (33) Country 268002 07.11.88 US UNITED STATES OF AMERICA

(43) Publication Date: 10.05.90 (71) Applicant(s) NORDSON CORPORATION (72) Inventor(s) CHARLES H. SCHOLL (74) Attorney or Agent SPRUSON FERGUSON (57) Claim 1. A nozzle attachment for use in an apparatus

for spraying hot melt adhesive which includes a gun body having a nozzle formed with an adhesive passage-

way for conveying heated hot melt adhesive and an air

delivery passageway for conveying pressurized air, said nozzle attachment comprising:

a one-piece annular plate formed with a

first surface on one side of said plate, and a second

surface on an opposite side of said plate;

a nozzle tip formed in said plate which

extends inwardly from said second surface toward said

first surface, said nozzle tip having an adhesive

discharge outlet locatea in substantially the same

plane as said second surface of said plate;

said plate being formed with a throughbore extending between said first surface of said one side

of said plate and said adhesive discharge outlet of

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I--CT I (11)42757/89 said nozzle tip, said plate being adapted to mount to -2-

said nozzle of said gun body so that said first

surface communicates with said air delivery passageway

in said nozzle and so that said throughbore communi-

cates with said adhesive passageway in said nozzle for

receiving heated hot melt adhesive, the hot melt

adhesive being ejected from said adhesive discharge

outlet of said nozzle tip to form an adhesive bead;

said plate being formed with a substantially

iI V-shaped annular groove forming first and second sidewalls each extending inwardly from said second surface toward said first surface and intersecting one

another, one of said first and second sidewalls of ii said V-shaped annular groove forming the outer surface

of said nozzle tip;

i! said plate being formed with a plurality of

air jet bores extending from said V-shaped annular I groove to said first surface of said plate, said air 6 '2

jet bores communicating with said air delivery pas- sageway in said nozzle for transmitting air there- through, said air jet bores each having a longitudinal

axis extending substantially perpendicular to the other of said first and second sidewalls of said V-shaped annular groove, said air jet bores being formed at an angle with respect to said throughbore in

said plate to direct pressurized air flowing there- through substantially tangent to the outer periphery of said adhesive bead ejected from said adhesive discharge outlet of said nozzle tip to form said adhesive bead in elongated adhesive fibers and to

I

_.1 I (11)42757/89

impart a twisting motion to said elongated adhesive

fibers to form a spiral spray pattern of elongated

adhesive fibers for deposition on a substrate. 4. Apparatus for spraying hot melt adhesive,

comprising:

a gun body having a nozzle formed with an adhesive passageway communicating with a source of

heated hot melt adhesive and an air passageway commu-

nicating with a source of pressurized air;

a one-piece annular plate formed with a boss s extending outwardly from a first surface of said plate

and a nozzle tip extending inwardly from a second I surface of said plate toward said first surface, said

nozzle tip having an adhesive discharge outlet located ii

in substantially the same plane as said second surface

of said plate, said plate being formed with a through-

bore extending between said boss and said adhesive

discharge outlet of said nozzle tip;

said plate being formed with a substantially

V-shaped annular groove forming first and second

sidewalls each extending inwardly from said second

surface toward said first surface and intersecting one

another, one of said first and second sidewalls of said V-shaped annular groove forming the outer surface

of said nozzle tip;

said plate being formed with a plurality of

air jet bores extending from said V-shaped annular groove to said first surface of said plate, said air jet bores each having a longitudinal axis extending substantially perpendicular to the other of said first

(11)42757/89 L- and second sidewalls of said V-shaped annular groove

and at an angle relative to the longitudinal axis of

said throughbore in said plate;

cap means for mounting said plate to said

nozzle of said gun body so that said throughbore

formed between said boss and said adhesive discharge outlet of said nozzle tip communicates with said

adhesive passageway in said nozzle and said air jet

bores communicate with said air passageway in said I

nozzle, said throughbore receiving heated hot melt

adhesive from said adhesive passageway and ejecting I i the heated hot melt adhesive from said adhesive B discharge outlet of said nozzle tip to form an adhe- jj sive bead, said air jet bores receiving pressurized

air from said air passageway in said nozzle and directing the pressurized air substantially tangent to

the outer periphery of said adhesive bead to form

elongated adhesive fibers and to impart a twisting

motion to said elongated adhesive fibers to form a i i spiral spray pattern of elongated adhesive fibers for 1 deposition on a substrate. i

iiii 1

ill~--C fUilblilr~L4E~L ii i-.li .Yii LL_ .l i

S F Ref: 109271 FORM

COMMONWEALTH OF AUSTRALIA i PATENTS ACT 1952 i COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Class Int Class i iComplete Specification Lodged: Accepted: Published:

Priority:

Related Art

Name and Address of Appl icant: Nordson Corporation ,i 28601 Clemens Road Nestlake Ohio 44145-1148 UNITED STATES OF AMERICA

SAddress for Service: Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street 44 0 Sydney, New South Wales, 2000, Australia

Complete Spiecification for the invention entitled:

S Nozzle Attachment For An Adhesive Spray Gun

The followiing statement is a full description of this invention, including the t t best method of performing it known to me/us

5845/4

_Y,

Nozzle Attachment For An Adhesive Soray Gun

Abstract of the Disclosure

An apparatus for spraying heated hot melt adhesive in elongated strands or fibers in a con- trolled, spiral pattern upon a substrate comprises a

spray gun having a nozzle formed with an adhesive delivery passageway and an air delivery passageway both of which terminate at the base of the nozzle. A

nozzle attachment in the form of'a one-piece annular

plate is mounted to the base of the nozzle by a cap.

The annular plate is formed with a throughbore which

receives hot melt adhesive from the adhesive delivery

passageway and ejects an adhesive bead through a 0 0 0 0

nozzle tip formed on the outer side of the plate 00

0 00 oo 0 opposite the nozzle. An annular groove formed in the 0 o o00 0 o

0000 outer side of the plate facilitates drilling of air o oo0000o

jet bores therein at an angle relative to the through-

bore and adhesive bead ejected therefrom. The air jet

bores receive pressurized air from the air delivery o0 a

passageway in the nozzle and direct jets of pressur- 0 00

0 00 ized air substantially tangent to the adhesive bead to 0 9 0000 form elongated adhesive fibers and to impart a spiral 0 S

motion to the elongated fibers so that they are formed 0100 0 I..i 4 in a compact spray pattern for deposition onto a 00oo000 0 0 substrate.

i

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Nozzle Attachment For An Adhesive Sorav Gun

Related Patents

This invention is related to U.S. Patent Application Serial No. 07/041,712, filed April 23, 1987, and entitled "Adhesive Spray Gun and Nozzle Attachment", which is assigned to the same assignee as

I 1 this invention.

Field of the Invention

I This invention relates to adhesive spray 0 guns, and, more particularly, to an adhesive spray gun 000

having a nozzle attachment for spraying hot melt

adhesive in beads or fibers in a controlled spray I pattern onto a substrate. 0 00

Backaround of the Invention

Hot melt thermoplastic adhesives have been 0 i 15 widely used in industry for adhering many types of

S0 products, and are particularly useful in applications

where quick setting time is advantageous. One appli-

cation for hot melt adhesive which has been of consid-

erable interest in recent years is the bonding of non- woven fibrous material to a polyurethane substrate in

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i- ill ~CYI~~I Ii~LP

1

articles such as disposable diapers, incontinence pads

and similar ar tides.

One aspect of forming an appropriate bond

between the non-woven layer and polyurethane substrate

of a disposabl.e diaper, for example, is to avoid loss

i of adhesive i in the valleys or gaps formed in the

irregular surf ace of the chopped fibrous or fluff-type

j i material whic h forms the non-woven layer. If the

i adhesive is dlischarged onto the non-woven layer in i

droplet form, for example, a portion of the droplets

can fall bet ween the gaps in the surface of the

fibrous, non-v /oven material. As a result, additional

quantities of adhesive are required to obtain the

desired bond strength between the polyurethane sub-

strate and nori-woven material.

Ii This Sproblem has been overcome in the prior

i art by formi Ig hot melt thermoplastic adhesives in

jelongated, th in beads or fibers which are deposited

atop the non- woven material and span the gaps in its

20 irregular sui :race. Elongated beads or fibers of

11,, adhesive have been produced in prior art spray devices

which include a nozzle formed with an adhesive dis-

charge openirng and one or more air jet orifices

through which a jet of air is ejected. A bead of

adhesive is ejected from the adhesive discharge

opening in th ie nozzle which is then impinged by the

air jets to attenuate or stretch the adhesive bead forming a thin fiber for deposition onto the sub- strate. Examples of spray devices of this type are ia disclosed in U.S. Patent Nos. 2,626,424 to Hawthorne, tt It Jr.; 3,152,923 to Marshall et al; and, 4,185,981 to r2 i-1 5 Ohsato et al.

ir i disposable In applications

diapers, it is such

important as the formation

to carefully of

ir ii control the spray pattern of adhesive fibers deposited

onto the non-woven substrate in order to obtain the ;a 10 desired bond strength between the non-woven layer and polyurethane t substrate using as little adhesive as i i possible. Improved control of the spray pattern of adhesive fibers has been obtained in prior art spray it devices of the type described above by impacting the i Ii 15 adhesive bead discharged from the nozzle with air jets i1 directed substantially tangent to the adhesive bead. i The tangentially applied air jets control the motion ii 1 of the elongated fibers of adhesive formed from the

it adhesive bead ejected from the adhesive discharge d o 20 opening in the gun nozzle, and confine the elongated :j fibers in a relatively tight, or compact, spiral pattern for application onto the substrate. Structure c~ which produces a spiral spray pattern of adhesive fibers for deposition onto a substrate is disclosed, for example, in the '424 Hawthorne, Jr. patent and the

'981 Ohsato et al patent mentioned above.

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I L. L n- -i-i ~i i LI L I

.a I- -4-

In order to produce a compact spiral spray pattern of adhesive fibers in the spray devices described above, it is important to ensure that the

air jets are directed tangentially relative to the i I bead of adhesive ejected from the nozzle of the spray

device. This requires accurate placement of the bores

or passageways through which pressurized air is

ejected from the nozzle or gun body of the spray

device, which are typically on the order of about

0.015 to 0.020 inches in diameter. The boring or drilling of passageways having such a small diameter

at the appropriate angles in the nozzle and/or gun

o ,oa body of prior art spray devices is a relatively

expensive and difficult machining operation. 0

15 Many problems with prior art adhesive fiber 0 o 0

spray systems have been overcome by the nozzle attach- 0D0

ment disclosed in U.S. Patent Application Serial No.

07/041,712, filed April 23, 1987 and entitled "Adhe- 0000 sive Spray Gun and Nozzle Attachment" which is 00 0 00 20 assigned to the same assignee as this invention. The

nozzle attachment of that invention is adapted to (O C 000 mount to the nozzle of a standard adhesive spray gun 0 00

which is formed with an adhesive discharge opening 0000U o) r 9 00000 connected to an adhesive passageway in the gun body 0 (00 000 V 0) and an air discharge opening connected to an air

passageway in the gun body. The nozzle attachment is

a one-piece annular plate formed with a boss extending outwardly from a first surface of the plate and a nozzle tip extending outwardly from a second surface of the plate. A throughbore is formed between the boss and nozzle tip which communicates with the adhesive discharge opening in the nozzle of the gun body when the plate is mounted to the nozzle. Heated hot melt adhesive is transmitted through the adhesive passageway in the gun body, out its adhesive discharge opening and then into the throughbore in the plate.

The adhesive is ejected as a bead through the nozzle tip toward a substrate.

The annular plate is formed with a V-shaped I notch or groove which extends from its first surface t

having the boss toward the second surface formed with t t I4 15 the nozzle tip. The V-shaped groove is provided to t

assist in drilling air jet bores in the plate through

which jets of pressurized air are directed at an angle

of about 30° and tangent to the adhesive bead ejected 4 t 4

4i I from the nozzle tip. The annular V-shaped groove is i (1 t 20 formed with two sidewalls, one of which is disposed I *S I

substantially perpendicularly to the longitudinal axis e f it of each of the air jet bores. This construction

permits the drill bit to contact the plate at the ~4 t i t ti ~t surface of one of the sidewalls in the V-shaped groove I

which is substantially perpendicular to the axis of

movement of the drill bit, at an angle of abut

300 to the first and second surfaces of the plate. As

L_ i ~.ii a L i __li _FI

I--

a result, sliding of the drill bit relative to the

plate is minimized during the drilling or boring

operation which helps locate the air jets bores at the

desired angle in the plate. While the nozzle attachment disclosed in

Serial No. 07/041,712 solves many of the problems of

prior art devices designed to spray adhesive fibers, Si some deficiencies have been discovered in certain

applications. It has been found that the formation of il

10 a groove in the relatively thin nozzle attachment or 0

plate can result in deflection of the nozzle attach-

ment during operation. This deflection can form a

leakage path at the interface between the nozzle

attachment and nozzle of the spray gun. In some #il 15 instances, it has been found that hot melt adhesive to,,

entering the nozzle attachment has flowed along this

leakage path and been deposited in the V-shaped groove

where the air flows into the air jet bores. This can iii, 0 *4 clog the air jet bores and restrict the flow of air

necessary to attenuate or stretch the adhesive bead to

O 8I form adhesive fibers.

Another potential problem with the nozzle

i, lot attachment of Serial No. 07/041,712 is that the air

jet bores are drilled in the plate or nozzle attach- ment from the inner side or surface which contacts the

nozzle toward the outer side or surface formed with

the nozzle tip. Because the air jet bores are so

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j iii--LL..i_-i _j i small in diameter, .015 to .020 inches, it is possible for the drill bit to drift or move off line in the course of passing through the nozzle attachment from its inner side to the outer side. As a result, the discharge outlet of the air jet bores at the outer side of the nozzle attachment might be slightly out of position and this can affect the efficiency of the 1 nozzle attachment in forming adhesive fibers because the air jets may not impact the adhesive bead pre- cisely tangentially thereto.

The nozzle tip of the nozzle attachment

0 disclosed in Serial No. 07/041,712 protrudes from the S, 15 outer surface thereof when mounted to the nozzle of Q 000 000 00 the gun body, and extends outwardly from a mounting

nut which secures the nozzle attachment to the nozzle 0 00

0"00 of the spray gun. A cavity or space is thus formed

between the nozzle tip and such mounting nut. When the spray gun is operated intermittently, it has been 0000 o^ o found that cut-off drool, adhesive remaining 0 0 o00 after the gun is shut off, can collect in the space or

o o° cavity between the nozzle tip and mounting nut. This 6 0

o0 o6 cut-off drool might collect and partially block the

0 0o 25 discharge outlet of the air jet bores formed in the a o

000 00 o nozzle attachment, thus affecting the performance of 0 0

the nozzle attachment in forming adhesive fibers.

Additionally, the protruding nozzle tip is exposed and

'8: -8-

can be damaaed if it contacts the target substrate or

other object during operation of the spray gun.

Summary of the Invention

It is therefore among the objectives of this

invention to provide a nozzle attachment for use in a

spray gun for spraying hot melt adhesive in elongated

beads or fibers onto a substrate which is relatively

inexpensive to manufacture, which provides accurately

located air jets to attenuate or stretch an adhesive

bead to form adhesive fibers, which avoids leakage of

adhesive from the spray gun, which is rugged in

construction, which resists clogging with adhesive and

which is readily installed on a standard spray gun to

convert the spray gun to one capable of spraying hot

melt adhesive in fiber form. These objectives are accomplished in a

nozzle attachment for a hot melt adhesive spray device

which includes a gun body and a nozzle having an

adhesive passageway and an air passageway. The nozzle 4 4 0

attachment is a one-piece annular plate which is

O. mounted by a cap or nut to the nozzle of the gun body.

The nozzle attachment or plate is formed with a

throughbore adapted to connect to the adhesive

passageway in the nozzle, and a plurality of spaced

air jet bores are formed in the plate which communi-

cate with the air passageway in the nozzle. An

adhesive bead is ejected from the throughbore in the

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L~ i. ii i i-i li- ;ii plate which is impacted by air jets from the spaced air jet bores. The air jets are directed tangentially to the bead to both stretch the bead forming hot melt adhesive fibers, and to impart a spiral motion to the adhesive fibers so that they are deposited in a controlled spray pattern upon a substrate.

The one-piece annular plate is formed with a

boss extending outwardly from a first, inner surface

of the plate, and a nozzle tip extending inwardly from

a second, outer surface of the plate toward its inner surface. A throuahbore is formed between the boss and

nozzle tip which communicates with the adhesive

passageway in the nozzle when the plate is mounted

thereto. Heated hot melt adhesive is transmitted

through the nozzle and then into the throughbore in

the plate from which it is ejected through a discharge

outlet of the nozzle tip toward a substrate.

The annular plate of this invention is

relatively thick from its inner surface to its outer

surface in order to resist deflection with respect to

the nozzle during operation of the spray gun. The

inner surface of the plate is flat or planar except

for the boss which extends outwardly therefrom. This

inner surface forms an effective metal-to-metal seal

with the mating surface of the nozzle of the spray gun

when the plate is mounted thereto. As a result,

adhesive transmitted from the nozzle into the

I throughbore of the plate is prevented from leaking at

the interface therebetween.

The annular plate forming the nozzle attach-

ment of this invention is formed with an annular, V-shaped notch or groove which extends inwardly from

j the outer surface of the plate toward its inner I surface. This V-shaped groove is provided to assist

in the drilling operation of the air jet bores through

which jets of pressurized air are directed from the

air passageway in the nozzle, through the plate and

then into contact with the adhesive bead ejected from

j the discharge outlet of the nozzle tip.

In the presently preferred embodiment, each

of the spaced air jet bores is drilled at an angle of

approximately 30° with respect to the longitudinal Saxis of the throughbore in the plate from which the

adhesive bead is ejected. In order to assist in

j drilling the air jet bores at this angle, the V-shaped I I, notch or groove at the outer surface of the nozzle It 20 attachment forms two sidewalls. One of the sidewalls 1 I

I is oriented substantially perpendicularly to the i I I longitudinal axis of each of the air jet bores. The

other sidewall forms the outer surface of the nozzle

tip such that the discharge outlet of the nozzle tip

is substantially coplanar with the outer surface of

the plate. The sidewall of the V-shaped groove

oriented perpendicularly to the longitudinal axis of

I--YLL-- the air jet bores permits the drill bit to contact the plate at a suriace which is substantial.ly perpendicu- to.C'. rthe aX:Ls oz movement of the drill bit even though -the drill bit is moved at- 3(Q~ angic with respect to the outer surface of the plate. The air jet bores formed in the no2ze attachment of this invention are drilled by movement of a drill bit from the outer surface of the no2zle attactunent where the V-shaped groove is formed, toward the inner surface of the nczzle attachment which contacts the nozzle. As mentioned above, it ~s important that ths outlet cf the air jet b-ores L-e precisely located so that the air jets discharged therefr-om tangentially impact the adhesive bead dischar~ed from the nozzle L4of the nczzle attach- "Ren". Because tLhe drill7ing operatio- begins at the outer sur C o; the noz~ld! ~a~tt,lt t:he c- of the ouitlet of the air jet bores at such outer surrace can be precisely controlled, Any drif4t of the U drill bit in moving througrh the nozzle attachment or plate has no affect on the location of the outlet of I ~Za~ZAZ~z> 4< the air jet bores at the outer surface of the plate, This had sometimes presented a problem in the riachin- ing of the nozzle attachment disclosed in prior Application Serial No. 07/041,712 wherein the di-illling operation proceeded -from the inner surface cf the plate toward the outer surface.

II.~UII-

In a presently preferred embodiment, the spaced air jet bores are also formed in the plate at

an angle relative to the outer periphery of the

throughbore and the adhesive bead ejected therefrom.

The longitudinal axis of each air jet bore is oriented

at an angle of approximately 100 with respect to a

vertical plane which passes through the longitudinal

axis of the throughbore in the plate and the center of

such air jet bore at the V-shaped groove in the plate.

As a result, the jets of pressurized air ejected from the spaced air jet bores impact the adhesive bead

discharged from the nozzle tip of the plate at its

outer periphery so as to impart a rotational movement

to the bead. The adhesive bead is attenuated or i stretched into elongated fibers upon impact with the

air jets, and these fibers are then rotated by the air

jets in a spiral motion to control the width of the

spray pattern applied to the substrate. 444 In the presently preferred embodiment, an 4 4t

2-~t 20 annular recess is formed in the nozzle attachment or 4 4 4 41 plate which extends inwardly at the peripheral edge of

the plate from its outer surface toward the inner

surface. This annular recess forms a seat which

receives the mounting nut or cap which mounts the

nozzle attachment to the nozzle of the spray gun.

Preferably, the outer surface of the nozzle attachment

and the discharge outlet of the nozzle tip are

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_i

"C coplanar with the mounting cap or nut when the nozzle

attachment is mounted to the spray gun nozzle.

This construction has two advantages.

First, there is no space or cavity formed between the

mounting nut and nozzle tip in which cut-off drool or

strands of adhesive could collect to block the air jet

bores. This had been a problem in the aforementioned

patent application Serial No. 07/041,712 wherein a gap

was formed between the nozzle tip and mounting nut.

Secondly, the mounting nut, the outer surface of the

nozzle attachment and the discharge outlet of the

nozzle tip are all coplanar. This prevents the nozzle 4,4 tip from contacting the substrate or another object

during separation of the spray gun where it could be 9

damaged.

The nozzle attachment or plate of this *14

invention provides an economical means to convert a

standard spray gun into one in which hot melt adhesive

4 4444 44 may be discharged in elongated strands or fibers for 44 4

20 applications such as bonding the non-woven and poly- 4f 44

urethane layers of disposable diapers or other 4I 4 .44,

hygienic articles. The construction of the nozzle

attachment or plate prevents leakage of adhesive at ~=Cj ~L~-J

its interface with the nozzle, facilitates the accu-

rate drilling of air jet bores so that the adhesive bead discharged from the spray device is consistently

formed into elongated fibers and resists clogging from build-uo of cut-off drool. The nozzle attachment or plate is easily removed from the spray gun and re- placed with another nozzle attachment of different size to accommodate different applications and/or different spray guns. Detailed Description of the Drawinas

The structure, operation and advantages of

the presently preferred embodiment of this invention will become further apparent upon consideration of the

following description, taken in conjunction with the

ii accompanying drawings, wherein:

iFig. 1 is a cross sectional view of a spray

i *gun incorporating the nozzle attachment herein with a

S schematic view of a manifold mounted to the spray gun; 'i i 15 Fig. 2 is an enlarged cross sectional view Sof the nozzle attachment herein showing an adhesive

bead impacted by air jet streams; and

Fig. 3 is a top plan view of the nozzle

attachment shown in Fig. 2.

,I 20 Detailed Description of the Invention

rI Referring now to Fig. 1, an adhesive spray

device 10 is illustrated comprising a gun body 12

I I having a nozzle 14 connected at one end, and an

adhesive manifold 16 and air manifold 17 mounted to

the gun body 12. The air manifold 17 is mounted to

the adhesive manifold 16 by two or more screws 19,

each of which extend through a spacer 21 ektending between the manifolds 16, 17. The nozzle 14 supports a nozzle attachment 18 from which a bead of heated hot melt adhesive is discharged and formed into a thin, elongated bead or fiber which is rotated in a compact spiral spray pattern onto a substrate, as discussed in detail below. The structure of the gun body 12 and manifolds 16, 17 are substantially identical to the i Model H200 spray gun manufactured and sold by the i assignee of this invention, Nordson Corporation of j 10 Amherst, Ohio. These elements form no part of the invention per se and are thus discussed only briefly herein.

1 As shown in Fig. 1, the upper portion of gun

body 12 is formed with an air cavity 20 which receives

i 15 the upper end of a plunger 22 mounted to a seal 24.

The seal 24 is slidable within the air cavity 20 and

provides an airtight seal along its walls. A collar 26 is mounted to the upper end of gun body 12, such as

by bolts 28, which is formed with a throughbore i 20 defining an inner, threaded wall 30. The collar 26 :I receives a plug 32 havir.g external threads which mate

with the threaded wall 30 of the collar 26. The plug 32 is hollow and a spring 34 is mounted in its interi-

or which extends between the top end of the plunger 22

and the head 36 of plug 32 having a screw slot 38. A lock nut 40 is threaded onto the plug 32 into engage-

ment with the top edge of the collar 26.

i i- -dl

The plug 32 is rotatable with respect to the

collar 26 to vary the force applied by the spring 34

against the top edge of plunger 22. In order to

rotate the plug 32, the lock nut 40 is first rotated

to disengage the collar 26 after which a screwdriver is inserted into the screw slot 38 in the head 36 of

plug 32 and rotated to move the plug 32, and in turn

increase or decrease the compression force of spring

34 within the collar 26.

The plunger 22 is sealed at the base of the air cavity 20 by a seal 42 which permits axial move-

ment of the plunger 22 therealong. The plunger 22

extends downwardly through the gun body 12 from the

air cavity 20 through a stepped bore 44 which leads

into an adhesive cavity 46 having a seal 48 at its

upper end and a plunger mount 50 at its lower end. A

spring 51 carried around the plunger 22 is disposed

within the adhesive cavity 46 and extends between the rn~

r: I seal 48 and plunger mount 50 to hold the seal 48 in r rt r L L place. This seal 48 and seal 42 aid in guiding the I axial movement of plunger 22 within the gun body 12.

The upper end of the nozzle 14 extends into

the adhesive cavity 46 and is sealed thereto by an

I I t 0-ring 52. The nozzle 14 is fixed to the gun body 12

by screws 54. The plunger 22 extends downwardly from

the adhesive cavity 46 and plunger mount 50 into an

-16- adhesive passageway 56 formed in the nozzle 14 which terminates at an adhesive discharge opening 57. Immediately upstream from the adhesive discharge opening 57, the adhesive passageway 56 is formed with a conical-shaped seat 58 which mates with the terminal end 59 of the plunger 22. As discussed below, move- ment of the plunger 22 relative to the seat 58 con- trols the flow of heated hot melt adhesive ejected from adhesive passageway 56 through its adhesive discharge opening 57. The nozzle 14 is also formed with a reduced diameter portion having external threads 60 which mate with internal threads formed in a cap 62. As de- scribed below, the cap 62 mounts the nozzle attachment

18 to the base of nozzle 14 in communication with the

I discharge opening 57 of adhesive passageway 56.

The gun body 12 is mounted to the adhesive

manifold 16 by mounting bolts 64. In turn, the

adhesive manifold 16 is supported on a bar 66 by a (I 20 mounting block 68 connected to the adhesive manifold fti 16 with screws 70. As illustrated at the top of Fig.

1, the mounting block 68 is formed with a slot 72

forming two half sections 73, 75 which receive the bar It 66 therebetween. A bolt 74 spans the half sections

73, 75 of the mounting block formed by the slot 72 and

tightens them down against the bar 66 to secure the

mounting block 68 thereto.

i_ 1 re J1

I

[1

B--18- LI The adhesive manifold 16 is formed with a

junction box 76 which receives an electric cable 78 to

i1 supply power to a heater 80 and an RTD 82. The heater

maintains the hot melt adhesive in a molten state

1 ii i when it is introduced into the adhesive manifold

through an adhesive inlet line 84 from a source of hot 16

melt adhesive (not shown). The adhesive inlet line 84 :i r communicates through a connector line 86 formed in the

1t i gun body 12 with the adhesive cavity 46. An O-ring

i is provided between the gun body 12 and adhesive

ii manifold 16 at the junction of the adhesive inlet line

84 and connector line 86 to form a seal therebetween. t I Operating air for the plunger 22 is supplied through

ri I

15 an inlet line

which is joined by 88 formed in the adhesive manifold 16

a connector line 90 to the air i iI cavity 20. The gun body 12 and manifold are sealed

i i aa thereat by an 0-ring 89. The air manifold 17 is formed with an air ;r S P inlet line 92 connected to an air delivery passageway ir iIr 20 94 formed in the nozzle 14 which terminates in an SI ft ft 14. annular chamber 95 at the base of the nozzle tE

O-ring seal 96 forms a fluid-tight seal between the

nozzle 14 and air manifold 17 at the intersection of

air inlet line 92 and air delivery passageway 94.

Referring now to the bottom of Fig. 1 and to

Figs. 2 and 2, the nozzle attachment 18 of this

invention is shown in detail. The nozzle attachment

-18-

LL L1 -r i. i c iii i. -i -C L ill ~_UIL it~ 18 is an annular plate having one side formed with a i first or inner surface 102 and an opposite side formed with a second or outer surface 104 spaced from the inner surface 102. For purposes of the present description, the term "inner" refers to a direction toward the nozzle 14, and the term "outer" refers to a direction away from the nozzle 14 with the nozzle attachment 18 mounted to the nozzle 14 as shown in Fig. 1.

A boss 106 extends outwardly from the inner surface 102, and a nozzle tip 108 extends inwardly

from the outer surface 104 in alignment with the boss

U. 106. A throughbore 110 is drilled in the nozzle

attdchment 18 between the boss 106 and nozzle tip 108

forming a discharge outlet 109 in the nozzle tip 108

which is coplanar with the outer surface 104 of nozzle St

attachment 18. The throughbore 110 has a diameter in

the range of about 0.010 to 0.040 inches, and pref-

erably in the range of about 0.0175 to 0.0185 inches. II

An annular, V-shaped groove 112 is formed in ft

the nozzle attachment 18 which extends inwardly from

its outer surface 104 toward the inner surface 102. The annular groove 112 defines a pair of sidewalls

114, 116 which are substantially perpendicular to one

another and intersect. In a presently preferred

embodiment, the sidewall 116 is formed at approxi- mately a 300 angle with respect to the planar outer

-19-

L, LL L; h -i -r i~-IL ~1_L Cj _1C. j_ -1_1 -ili

)rlp i--L

i. surface 104 of the nozzle attachment 18, and the sidewall 114 forms the outer surface of the nozzle tip

108. As best shown in Figs. 2 and 3, six air jet bores 118 are formed in the nozzle attachment 18 between the annular groove 112 and the inner surface 102, preferably at an angle of approximately 30° with

respect to the longitudinal axis of the throughbore 110. The diameter of the air jet bores 118 is in the

range of about 0.010 to 0.040 inches, and preferably

in the range of about 0.017 to 0.019 inches. The annular groove 112 facilitates accurate drilling of the air jet bores 118 so that they are formed at the desired angle relative to throughbore ii 110 and are precisely located at the desired position

:j 15 along the sidewall 116 of groove 112. By forming the sidewall 116 at a 30° angle relative to the upper

surface 102 of nozzle attachment 18, a drill bit (not shown) can enter the annular groove 112 in the nozzle i E O ii attachment 18 at a 30° angle relative to its outer I i )t

surface 104, but contact the sidewall 116 formed by ~f i i

d 111 the annular groove 112 at a 90° angle. As a result, i I the drilling operation is performed with minimal

4j slippage between the drill bit and

18. This allows the outlet 119 of the air jet bores nozzle attachment

118 to be precisely positioned at the sidewall 116 and oriented at the appropriate angles relative to throughbore 110. In the event of any drift of the

L-L. I- L L. ~ii. r 1 i -ri 1. r L ~i i ic ir. Li_- r- ii drill bit as it moves through the nozzle attachment 18 to the inner surface 102, the inlet 121 of the air jet bores 118 may be slightly out of position but would nevertheless intersect the annular chamber 95 formed in nozzle 14.

As shown in Fig. 3, the longitudinal axis of

each of the air jet bores 118 is angled approximately

100 with respect to a vertical plane passing through

the longitudinal axis of the throughbore 110 and the center of each such bore 118 at the annular groove 112. For example, the longitudinal axis 122 of air jet bore 118a is angled approximately 100 relative to

a vertical plane passing through the longitudinal axis

124 of throughbore 110 and the center point 126 of bore 118a at the annular groove 112 in nozzle attach-

ment 18. As a result, the jet of pressurized air 128

ejected from air jet bore 118a is directed substan- tially tangent to the outer periphery of the through-

bore 110 and the adhesive bead 130 ejected therefrom,

as described below.

Referring now to Figs. 1 and 2, the cap 62

is formed with an annular seat 132 which mates with an D I'' annular recess 134 formed in the peripheral edge of

nozzle attachment 18 which extends inwardly from its outer surface 104. The cap 62 is threaded onto the lowermost end of the nozzle 14 so that the boss 106 on

the inner surface 102 of nozzle attachment 18 extends

-21-

_i .i _1 ii. -r ;1 r; it within a seat 136 formed in the base of nozzle 14 at the adhesive discharge opening 57 of adhesive passage- way 56. With the nozzle attachment 18 in this posi- tion, the inlet of each of the air jet bores 118 communicates with the annular air chamber 95 formed in it the base of the nozzle 14 at the end of the air delivery passageway 94. No O-rings or other seals are required between the inner surface 102 of the nozzle attachment 18 and the nozzle 14 in order to create a fluid-tight seal therebetween and between the boss 106 and adhesive discharge opening 57. The nozzle attach- ment 18 is easily removed and replaced by another C, attachment of different size by rotating the cap 62

C, .0 out of engagement with the nozzle 14.

eIi 15 The operation of the spray device 10 of this invention is as follows. Heated hot melt adhesive is

introduced into the adhesive cavity 46 of the gun body

12 through the adhesive inlet line 84. Adhesive flows i from the adhesive cavity 46 into the nozzle 14 through Co a

S,,I 20 the adhesive passageway 56. With the terminal end 59 4 4 of the plunger 22 in engagement with the seat 58

formed at the end of the adhesive passageway 56, as

illustrated in Fig. 1, the adhesive is not permitted

to flow through the adhesive discharge opening 57 of

the adhesive passageway 56 to the throughbore 110. In

order to retract the plunger 22 and permit the flow of

adhesive into the discharge opening 57, operating air

IC~III~ LII~IIIIIIY

-23-

rrr is introduced through the operating air line 88 into

i. the air cavity 20 in the gun body 12. This pressur-

ized air acts against the seal 24 connected to the

plunger 22 which forces the plunger 22 upwardly so

that its terminal end 59 disengages the seat 58 at the

lower end of the adhesive passageway 56. The plunger

22 is returned to its closed position by discontinuing

the flow of air to the air cavity 20 allowing the

return spring 34 to move the plunger 22 back into a

seated position.

The flow of hot melt adhesive through the

adhesive discharge opening 57 of adhesive passageway

56 is transmitted into the throughbore 110 of nozzle

attachment 18 from which it is discharged through the

discharge outlet 109 of nozzle tip 108 to form the

adhesive bead 130. At the same time the adhesive bead

130 is formed and ejected from the nozzle attachment

18, pressurized air is directed through the air inlet

line 92, air delivery passageway 94 and air chamber

to the air jet bores 118 formed in the nozzle attach-

ment 18.

As best shown in Fig. 2, the air jet bores

118 are angled relative to the longitudinal axis of

the throughbore 110 so that the jets of air 128

flowing therethrough impact the adhesive bead 130

substantially tangent to its outer periphery at a

point spaced below the nozzle tip 108. The air ejected from the air jet bores 118 performs two functions. First, the jets of air 128 attenuate or stretch the adhesive bead 130 forming elongated strands or fibers of hot melt adhesive for deposit onto a substrate. Additionally, since the air jet bores 118 are oriented to direct jets of air 128 tangent to the outer periphery of the adhesive bead

130, the adhesive bead 130 and adhesive fibers formed

therefrom are rotated in a compact spiral path toward

I a substrate. As a result, a controlled pattern of

adhesive having a desired width is obtained on the

substrate.

While the invention has been described with :1 reference to a preferred embodiment, it will be I understood by those skilled in the art that various

changes may be made and equivalents may be substituted i for elements thereof without departing from the scope 'I of the invention. In addition, many modifications may

be made to adapt a particular situation or material to

the teachings of the invention without departing from .11

the essential scope thereof. Therefore, it is intend-

ed that the invention not be limited to the particular

embodiment disclosed as the best mode contemplated for

carrying out this invention, but that the invention

will include all embodiments falling within the scope

of the appended claims.

x

Claims (1)

1. ii

   The claims defining the invention are as follows: 1. A nozzle attachment for use in an apparatus

   j for spraying hot melt adhesive which includes a gun

   i body having a nozzle formed with an adhesive passage-

   iII j 5 way for conveying heated hot melt adhesive and an air

   delivery passageway for conveying pressurized air, i

   said nozzle attachment comprising: a i ti a one-piece annular

   first surface on one side of said plate, and a second plate formed with a

   surface on an opposite side of said plate; ii 'ii 10 a nozzle tip formed in said plate which I extends inwardly from said second surface toward said i

   first surface, said nozzle tip having an adhesive r o

   iii discharge outlet located in substantially the same ii It

   'i t plane as said second surface of said plate;

   i:I 'I 4

   said plate being formed with a throughbore extending between said first surface of said one side r ii of said plate and said adhesive discharge outlet of

   said nozzle tip, said plate being adapted to mount to S 1( a 4

   t t4 I said nozzle of said gun body

   surface communicates with said air delivery passageway so that said first

   i I 4 '4, t in said nozzle and so that said throughbore communi-

   cates with said adhesive passageway in said nozzle for

   I receiving

   adhesive heated

   being hot

   ejected melt

   from adhesive,

   said the

   adhesive hot melt

   discharge

   outlet of said nozzle tip to form an adhesive bead; said plate being formed with a substantially

   V-shaped annular groove forming first and second

   -LIL--~LI sidewalls each extending inwardly from said second surface toward said first surface and intersecting one another, one of said first and second sidewalls of said V-shaped annular groove forming the outer surface of said nozzle tip; said plate being formed with a plurality of air jet bores extending from said V-shaped annular groove to said first surface of said plate, said air jet bores communicating with said air delivery pas- sageway in said nozzle for transmitting air there- through, said air jet bores each having a longitudinal axis extending substantially perpendicular to the other of said first and second sidewalls of said

   V-shaped annular groove, said air jet bores being

   formed at an angle with respect to said throughbore in

   said plate to direct pressurized air flowing there-

   through substantially tangent to the outer periphery

   of said adhesive bead ejected from said adhesive

   A 4 t discharge outlet of said nozzle tip to form said 4 44

   adhesive bead in elongated adhesive fibers and to 4 A 44$, impart a twisting motion to said elongated adhesive

   A 1 50 fibers to form a spiral

   adhesive fibers for deposition on a substrate. spray pattern of elongated

   1! i';

   It

   -27- L 2. The nozzle attachment of claim 1 in which

   said air jet bores in said one-piece annular plate are

   formed at an angle of about 300 relative to the

   i longitudinal axis of said throughbore in said plate.

   i i 3. The nozzle attachment of claim

   the longitudinal axis of each said air jet bores forms 1 in which

   an angle of approximately 100 relative to a vertical t Ii plane passing through the longitudinal axis of said

   ii throughbore, the pressurized air ejected from said

   bores thereby being directed through said air jet

   bores substantially tangent to the outer periphery of 1i said adhesive bead ejected from said adhesive dis- r charge outlet of said nozzle tip. i i

   1 i i

   i

   i

   -27-

   i, I

   4. Apparatus for spraying hot melt adhesive,

   i comprising: a gun body having a nozzle formed with an I adhesive passageway communicating with a source of

   heated hot melt adhesive and an air passageway commu-

   nicating with a source of pressurized air;

   a one-piece annular plate formed with a boss

   Sextending outwardly from a first surface of said plate

   and a nozzle tip extending inwardly from a second i 10 surface of said plate toward said first surface, said

   nozzle tip having an adhesive discharge outlet located

   in substantially the same plane as said second surface

   of said plate, said plate being formed with a through-

   bore extending between said boss and said adhesive

   15 discharge outlet of said nozzle tip;

   said plate being formed with a substantially

   V-shaped annular groove forming first and second

   sidewalls each extending inwardly from said second

   surface toward said first surface and intersecting one

   another, one of said first and second sidewalls of

   said V-shaped annular groove forming the outer surface

   of said nozzle tip;

   said plate being formed with a plurality of

   air jet bores extending from said V-shaped annular groove to said first surface of said plate, said air

   jet bores each having a longitudinal axis extending

   substantially perpendicular to the other of said first

   -28-

   i and second sidewalls of said V-shaped annular groove and at an angle relative to the longitudinal axis of said throughbore in said plate; cap means for mounting said plate to said nozzle of said gun body so that said throughbore formed between said boss and said adhesive discharge outlet of said nozzle tip communicates with said adhesive passageway in said nozzle and said air jet bores communicate with said air passageway in said nozzle, said throughbore receiving heated hot melt

   A adhesive from said adhesive passageway and ejecting

   the heated hot melt adhesive from said adhesive

   discharge outlet of said nozzle tip to form an adhe-

   i sive bead, said air jet bores receiving pressurized

   i air from said air passageway in said nozzle and directing the pressurized air substantially tangent to

   i the outer periphery of said adhesive bead to form

   elongated adhesive fibers and to impart a twisting

   motion to said elongated adhesive fibers to form a

   spiral spray pattern of elongated adhesive fibers for

   deposition on a substrate. !i i I

   The apparatus of claim 4 in which said nozzle of said gun body is formed with a seat which

   receives said boss of said plate forming a fluid-tight

   seal therebetween.

   i 6. The apparatus of claim 4 in which said I one-piece annular plate has a peripheral edge formed

   i with a recess which extends from said second surface toward said first surface of said plate.

   The apparatus of claim 6 in which a portion

   of said nozzle of said gun body is formed with exter- Ito

   1 'I 0 nal threads, said cap means comprising a cylindrical-

   shaped member formed with a throughbore defining an

   0 5 inner wall having threads adapted to mate with said

   external threads of said nozzle, said cylindrical- 0ar4 i shaped member being formed with an annular seat which Do mates with said recess formed in said one-piece 6 4A

   00 0 A 4 annular plate to support said plate, said cylindrical- '1 0 00 4 10 shaped member being threaded onto said nozzle to place (4 0

   said throughbore of said plate in communication with 4 0 4

   said adhesive passageway in said nozzle. 0 4 0P(

   001 DATED this NINTH day of OCTOBER 1989 Nordson Corporation

   Patent Attorneys for the Applicant SPRUSON FERGUSON