Note: Descriptions are shown in the official language in which they were submitted.
1~ ~3~
Our lleference: CA~-115-A
~AN ADJUSTMENT FOI~ PAINT SP12AY ~UN
UACKGROUND OF THE INVENTION
. _
In conventional paint ~pray guna, a atream of paint
under pre~ure i~ discharged from a relatively ~mall ori~ice in a
nozzle while air under pre~sure is di~charged radially inw~rdly
into the ~tream from an annular opening ~urrounding the nozzle
clo~ely adjacent the paint di~charge orifice to ~tomize the
~tream o~ palnt into a spray o~ fine particle~. Tha epr~y thuo
prodùced move0 aw~y from the gun in ~n exp~ndin~ conic~l p~ttern
whoae apex ia ut the nozzle.
It i~ fre~uently desired to modify the circular cro~-
section of the normal conical ~pray pattern by transforming thi~
pattern into one of a narrowed and elongated generally
elliptically ~haped cros~-~ection ~o that the ~pray pattern more
clo~ely re~emble~ that of a ~lat ~ided f~n.
In prior art ~pray gun~, ~anning o~ the ~pray p~ttern
ia typically acco~pli~hed by providiDg on the ~ront of the air
cap a pair of diametrically oppo~ed porta Dpaced radially
outwardly from oppoeite side~ of the annular ~ir di~char¢~
opening and orie~ted to direct air jet~ toward oppoaite ~idee o~
the ~pray pattern at a loc~tion 0paced a short di~tance forw~rdly
from the nozzle orifice. The~e jet~ have the ef~ect o~
flattening the ~ides of the conical ~pray pattern a~ain~t which
they are directed. At any given di~tance ~rom the noz~le, this
- 25 action trflnaform~ the normally circular cro~ ection o~ the
conical spray into a generally elliptically ~haped cro~s-e~ction
who~e major axis i~ somewha-t greater than the origin~l cone
diameter and who~e minor axis i~ ~omewhat le~s th~n the ori~inal
cone diameter. The "flatnes~" of the elliptical cro~s-6e¢tion
will incre~se with an increase o~ the pre~ur0 ot which air i~
expelled fro~ the diametri~cally oppo~ed fanning port~.
~, ~3~6~
In prior art ~un~, ad ju~tlDent of -the fanning of th~
~pray i~ typically made by rotatively adju~ting th~ air cap.
This udjuat~ent exerts a valving aCtioD which s~tabli~hes m~ximum
air flow when tl~e di~trically oppoued volve port~ li in eitller
a vertical plan~ containing the nozzle sxi~ or Q horizontal pl~ne
containing the nozzle axi~. The flow ~rom the fanning part~ i~
reduced aR the air c~p i~ rotated to become æ~ro when the f~nning
ports ~re ~idway b~tween tha hori~ontal ~nd vcrticul po~ition~
referred to above~ When the fanning port0 are ~t thi~ midway
position, the ~pray ~s~u~e~ it~ original conic~l ~orm.
While the foregoing ~rr~ngement provide~ for adjustment
to th~ f~nning of the ~pray, thi~ sdju~tm~nt i~ dependent upon
the rot~ted pO~itiOII of the air cup obout t}le nozzle ~xl~.
Adju~tm0nt of the Yan width (minor axi~ of thc olliptical ~Rn
cro~ ection) to a width between ~aximum or un~odified conical
0prsy und minimum width require~ the ~ir cap to have its port~
located in a genersl plane inclined from the vertic~l. Thi~
incliDstion o~ the fanning port~ e~tabli~he~ the ~ngle th~ ~a~or
QXi0 of the elliptical configur~tion will a~u~e with re~pect to
the vertic~ itu~tion which io inconveniont to th~ opor~tor
who would pr~fer that thi~ ~jor axi~ be either vertical or
horizontal for sll de~r~e0 of fennin~.
The present invention i~ directsd to a ~pray ~un 1D
~hich f~nning may be adju~t~bly controlled completely
5 indspendently o-~ the rotative orientation o~ ~he eir c~p.
SUMMARY OF T~IE_INVENTION
In accordance with the pre~ent invention, a p~iDt 0prBy
gun include~ a main hou~ing ~ro~ which a hollow tubular ~e~ber
project~ forwardly. The p~int ~pr~y nozzle, of conventional
con~truction, i~ threadably ~ounted at the forward end of thi~
tubular member who~e interior communicates with a ~itting in the
h~u~ing to which a supply of p~int under pre~re i~ attached.
~3~
A generally cylindricul hou~in~ exten~io~ mounted on
the hou~ing in coaxiel ~urroundin~ relation~hip to th~ tubular
me~ber an~l nn ~ir cup i~ threededly attached to the forward end
of this tubular exten~i~n to dufin~ en internal ~nnulur air
chamber within the exten~ion 3urroundin~ the tubular paint
carrying mel~ber. The air cap is provided with a central air
di~churge openiD~ through which air is di~ch~r~ed to ~tomize
paint di~charged under pre~sure from the noz~le ori~ice into
~pruy.
The rearward or inner ~ide of the air cap i~ formed
with ~ rearwardly opening counter bore which define~ a emooth
continuation o~ the inner ~ide wall of the extension o~ the
hou~in~. The counter bore in the air cap terminates at u
radially inwardly projecting shoulder and passage~ extend through
the air cap ~rom diametrically oppoYed inlets at the juncture o~
the ~houlder aDd counter bore to di~etrically oppo~ed fenning
porta oriented to discharge air against oppo~ite ~ideo o~ the
paint spray cone. A cylindrical valve member iA ~lidably
received within the counter bore and provided with un annular
radiel ~kirt ~t it~ forwerd end which, when ~eated aguin~t ~ho
rudial shoulder on the air cap wlll ceal eh~ inlst opunin~ o~
the pa~sage~ in the eir cup which lead to the fannin~ port~. Tho
~kirt defines a central opening through the forward ~nct o~ the
air cylinder which is of a diameter sub~tantially larger then the
tubular hou~ing member ~o that air can puY~ ~t ~ll time~ from the
interior of the cylindrical air cylinder to the central air
disch~rge openin~ o~ the air cap. A portion of the wall of the
cylinder iB provided with an opening BO that air can paB8 through
o ~itting on the hou~inl~ into the interior o~ the hou~iag
extension ~nd thence throueh the openirlg to the interior of thc
air cylinder. The re~rw~rd end o~ the air cylinder i~ ~orm~d
with an openin~ which i~ ~lid~bly receiv~d upon th~ tubular paint
pa~aage member of the housing. A control rod i~ coupled to the
resrward end of ttle ~ir cylinder and extend~ re~rwurdly to thJ
re~r end of th~ housing where it ia ~tt~hed to ~ ~anual
~dju~tment l;lember thread~bly r~ceived in the houaing. By
threading the adju~tmsnt member iDto or out o~ the housing, the
position of the r~dial akirt o~ the air cylinder ralative to the
radi~l shoulder on the air cap ~ay be varied at will to p~rtially
or fully open or cloae the inl~t~ to the air cap pu~a~ea leadin~
to the fanning port~.
Other objecta und features of the invention will become
apparent by reference to the ~ollowing ~pecific~tion Qnd to the
dr~wings.
IN TI~E DRAWINGS
Fig. 1 is ~ side view of ~ paint ~pr~y gun embodyiDg
the preaent invention;
Fig. 2 is a d~tailed cros~-~ectional view tallan on a
centr~l vertical pl~ne throu~h the forw~rd portion o~ the gun o~
Fig. l;
Fig. 3 i8 a detailed aide ~iew of the rearw~rd portion
of tha gun of Fig. 1, with cert~in parts broken away or ~hown in
~ection;
~ ig. 4 i~ a per~pectivc view of the ~ir cylinder ~nd B
portion of the control rod of the gun o-f Fig. l; and
Fig. 6 i~ a front view of the nozzle of the gun of Fig.
1.
~ efsrring firat to Figs. 1 and 2, a ~pray gun embDdyin~
the preaent invention includes a piatol-like main houfling
designated generally 10 havin~ ~ generally cylindrical exten~ion
12 fixedly ~ecured to it~ ~orw~rd end. An ~ir CHp 14 i~ ~ixedly
mounted on the front end of extension 12 a~ by an iDternally
threaded ~nnular ring 16 formed at it~ forward end with e
radially inwardly projecti~ng flsn~e 18 (Fig. 2) axially confined
- ~ 3~
to the main body of the cap a~ by a C ring 20 re~iliently seuted
within a circumferential notch 22. The ~kirt 16 iB freely
rot~table relative to the main body of ~ir cap 14. A nozzle 24
project~ coMxially through a central opening 2~ (Fig. 2) in tho
forward end of air cap 14~
Nozzle 24 is of conventional con~truction ~nd, a~ be~t
seen in Fi~. 2, i~ formed witll a forwardly convargent tepered
bore 2~ which ~er~in~te~ at an orifice 30 at the front ~nd of the
nozæle. Noz~le 2~ is ~ormed with ~ threuded ~hank~3;2 which i~
threadably received within the forward end of a forwardly
projecting hollow tubular member 34 integrally formed on m~in
hou~ing 10. Paint under pre~ure iB Bupplied to the central
pu~age 36 which extend~ through tubular ~e~ber 34 via a fittin~
38 threadably received within hou~ing lD ~nd huving ~ centr~l
pa~sage 40 in communication with pe~a~e 36. Th~ rear or ri~ht
hQnd end of pa~s~ge 36 as viewed in E'ig. 2 is clo4ed by ~
threaded plug 42 which al~o ~lidably support~ and guid~ ~n
clon~te rod-like needle v~lve 44 h~vin~ a tapered forward e~d 46
; which m~y be ~eated in the conical bore 28 o~ nozzl~ 24 to clo~e
the orifice 30.
Referriilg now to Fig. 1, a trigger 47 i~ pivotally
mounted upon housing 10 to eng~ge en enl~rged diameter portion 4B
for~ed on needle valve 44 to draw the valve to the right a~
viewod in Fig~. 1 and 2 when trig~ur ~7 i8 ~queezed. Rod ~4
extends resrwardly past the trigger and it~ enlarged dia~eter
aection 48 continue~ throu~h hou~iDg 10 to be coupled to An
adju~tment knob 50 threadsbly mounted within the hou~ing.
The couplin~ between needle vslve 44 ~nd adju~ting knob
50 i~ a 9pring loaded coupling of conventional construction which
act~ to continuou~ly bias needle valve 44 to the left a0 viewed
in Figs. 1 and ~ to it~ closed seated po~ition within nozzlc 24.
The adju~tm0nt knob 50 e~entially locQte~ the end li~it o~
~, ~3~ 7 ~
movement of the needle ~alve 44 to the right a~ viewed in Figs. 1
und 2 to e~tabli~h ~ ~llaximum opaning of noz~le 24 wh~ll trigg~r 47
i8 fully depre~ed. This arrangement for controlling the flow of
paint under pr~sure from orifice 30 i~ conventionul.
Referring now particulhrly to Figs. 2 and 5, from Fig.
5 it i~ ~een thut nozzle 24 is formed with ~ plurality of
radially projecting win~s 52 whose radially outer end~ lie on a
cylindrlcal ~urface coaxial ~lth the axi~ o~ noz~le Z4. The
re~rwurd ~ide of air cap 14 i~ formed with a counter bore 54 of a
diameter such that the outer end~ of wings ~2 o~ tha nozzle ere
slidably received within bore 54. ~t it~ inner end, counter bore
64 mer~eH with an inclined conical bore 56 which extsnds from
counter bore 54 to pierce the front ~ide of ~ir cap 14 to
est~bli~h o diecharge openin~ 26 surrounding ths forw~rd tip of
nozzle 24. The inclin~tion of the wall of the coniccl bore 66
and the inclinution o~ the for~ard side of no~le 24 a~ at 58 ~nd
the axial dimen~ions of the air cap and nozzle are such that an
air pa~sage i8 provided, when the no2zle ~nd ~ir cap ~re
ae~embled in the gun, between di~charge npenin~ 26 ~nd a cha~ber
60 constituted by an enl~rged diameter counter bore ut the
rearward ~ide of air c~p 14. Thi~ paB~a~e ext~nd~ from openin~
26 through sp~ce between the oppoaed inclined ~ur~oc~ ~6 o~ the
air c~p and 5B o~ the nozzle und thence throu~h the ~pace~
between adjacent wing~ ~2 o~ the nozzle.
Hou~ing exten~ion 12 i~ ~ormed with e bore 64 in it0
forwnrd end of the same dismeter a~ the mating counter bore 62 in
~ir cap 14, nnd bores 62 und 64 slidably receive the forwnrd end
o~ a hollow cylindrical air cylinder 66. Air cylinder 66 iB
formed with a bore 68 in it~ forward end wnll 70 which i~ of a
dinmeter larger thnn the outer diameter of tubul~r mcmber 34 o~
the ~ain hou~ing ~o thut chnmber 60 within nir cap 1~ i~ nlw~y~
in communicction with the ~ollow interior of air cylinder 66.
~3~
Th~ interior of air oylinder 6~ is in turn in con~tant
communication wi~h sn air chamber 72 formed within exten~ion 1~
via a cutout portion 74 in the air cylinder. Air under pre~ure
may be supplied to chamber 72 vis a fitting 76 threaded into
exten~ion 1~ ~nd hnving an air ~upply passage 78.
The rear wall 80 o~ cylinder 66 i~ formed with ~ bore
82 which slidably receive~ tubular member 34 of m~in hou~ing 10.
At the upper ~ide o~ cylinder 66 ear it~ rear wall, a
T s31uped slot 84 is formed to receive the end of an uctuatin~ rod
86. A~ best ~ee in Fig. 4, ~lots 88 sre formed in oppoHite
sides of the forward end of rod 86 ~o th~t when the end of tbe
rod i~ ~eated in T ~lot 84, the rod and cylinder ere coupled to
ench other for concurrent axi~l movement in either direction.
As be~t seen in Fig. 2, rod 86 extend~ rearw~rdly ~ro~
cylinder 66 throu~h a bore 90 in housin~ 10. Re~erring now to
~ig. 3, actu~ting rod 86 i~ formed with a reduced diemeter end
section 92 at it~ rearward end which pas~ rearwardly through a
bore 94 in an adju~tment ~crew 96. A knurled nut 98 thre~dably
received on the end o-f portion 92 of UCtUatiDg rod 86 uxially
~ixe~ rod 86 to ~dju~tment ~crew 96 while ~ccommvdatin~ rotery
movement u~ screw 96 relutive to rod a6. ~od 86 is re~trained
B~in~t rotary movement by the enga~ement betwaen the ~lots 88
(Fig. 4) in the forward end of rod 86 and the wall~ o~ tbe T ~lot
84.
Adjustment ~crew 96 i~ threadably received a~ at 100
within a fitting 102 threadably locked to housing 10. Threading
of adjustment screw 96 into or out of ~itting 102 iB tran~itted
by actuatil)g rod 86 to alr cylinder 66 to axially shi~t air
cylinder 66 relative to air cap 14.
neturning now to Fig. 2, Q pair o~ fnll control pa~ageB
104 are formed through air c~p 14 to extend from ch~mber 60 in
the air cap to inwardly inclined uir di~charge port~ 106.
L3~ ,f;~
In Fig. 2, ~ir cylinder 66 i~ shown ~t its maximum
opened po~ition in which air under pres~ure flowin~ into chsmber
60 from fitting 76 c~n pa89 freely both to the centrsl opening 26
of air cap 14 to utomize ~ paint stream i~uing under pre~ure
5 fro~ nvzzle ~0 ~d ~l~o freely tllrou~!l p~s~u~e~ 10~ to b~
di~charged from port~ 106 again~t oppo~ite ~ide~ o~ the conic~l
~pray of paint issuing from nozzle 24. It i~ believed ~pparent
that a~ air cylinder 66 is moved to the left from its Fig. 2
po~ition by manipulation of adjustment knob 96, tha ~ront wall 70
of air cylinder 66 will be advallced toward the inlet openin~ lOB
of pa~sage~ 104 and a8 the front wall 70 of cylinder 66 ~ov~
into contact with ths radial shoulder between counter bore~ S2
and 54 in the nozzle, the~e inlet opening~ will be progre~3ively
block~d ~nd eYentually sealed by forw~rd wull 70. ~y adj~Atably
po~itioning forw~rd w~ll 70 of ~ir cylinder ~6, a variabl~
re~triction to the flow of air through pass~ges 104 and the
fanning port~ 106 is av~ilable. Thi~ control of the fannin~ i~
independ~nt o~ the rotative po~ition of ~ir cap 14 ~bout the
nozzle ~xi~.
While one embodiment of the invention has been
de~crib~d in detail, it will be apparent to those akilled in the
art the di~closed embodiment may be modified. ~herefore, th~
foregoing de~cription i~ to be con~idered exemplary rather thall
limiting, and the true scope of the invention i~ that defined in
the following claims.
