Note: Descriptions are shown in the official language in which they were submitted.
1'~9~729
SEALLESS DISPENSING MECHANISM
BACRGROUND OF ~E TNVENTION
I. Field Qf ~h~ I~vention
The pre6ent invention relates generally to fluid
dispensing mechanism~ and, more particularly, to an
improved di~penser of ~impliPied construction which
does not require seal~, particularly sliding seals,
or springs for its operation, yet applies precisely
controlled quantities of the fluid to a receiving
surface.
II. e6cription Qf the Prior ~
There are a number of known designs for dispensing
fluids such as adhesives, sealants, and the like, at
accurately controlled flow rates, in accurate
quantities, and for accurate placement on a receiving
surface.
In one instance, a spring biased piston is
pneumatically operated to open and cloge a valve, as
2~ needed, to control the flow of fluid to be dispensed
from an outlet nozzle. The piston is provided with
seals to prevent flow of the fluid in directions other
than through the valve and the6e seals are 6ubject to
deterioration and wear, particularly when the fluid
being dispensed is heated.
129~7Z9 ``
In another known dispenser design, a diaphragm is
pneumatically operable to allow or interrupt flow of
the fluid to a dispensing nozzle. The diaphragm can be
moved by an actuating rod between a bowed position
enabling flow to occur between inlet and outlet
conduits and a planar position interrupting such flow.
Again, proper sealing of the valve is a continuing
problem. Specifically, it has not been possible
heretofore to adequately seal the unit to prevent flow
of the fluid into the actuating mechanism regardless of
the type or number of seals being employed by the
mechanism.
Another type of dispenser utilizes a positive
displacement type of valve in which a quantity of the
fluid ~8 admitted into a chamber whereupon a piston
then forces that quantity out through the dispensing
outlet or nozzle. Again, in this instance, seals are
necessary components of the mechanism and are not
totally effective in satisfying their intended purpose.
In each of the foregoing instances, loss of the fluid
that does not issue from the outlet nozzle but finds
its way instead into other cavities of the dispen6ing
mechanism is not the primary concern. Rather, when the
fluid is a sealant or adhesive material, it
subse~uently accumulates, then hardens, and thereby has
a detrimental effect on the operation of the dispensing
mechanism, even to the point of rendering it
inoperative.
~,'29~7;~9
Yet another known design of fluid dispenser utilizes a
pinch valve according to which an actuator is
selectively moved into or out of engagement with
flexible tubing which extends from a source of supply to
the dispensing head. While seals are not a particular
problem with this design of dispenser, the length of the
tubing necessary for this design is sufficiently long
that it undesirably results in a delayed response time
between the operation of the valve and the resultant
flow of fluid being dispensed from the nozzle. This, in
turn, causes inconsistent flow through the nozzle
thereby reducing accuracy, namely, placement of a
particular quantity of fluid at a particular location at
a particular time.
SUMMARY OF THE INVENTION
It was with knowledge of the prior art, generally as
noted above, and the problems existing which gave rise
to the present invention. The present invention relates
to a simplified fluid dispenser for dispensing precise
quantities of fluid without requiring special seals or
springs. It comprises a housing defining a fluid
reservoir having an inlet for delivery of pressurized
fluid to the reservoir, and including a valve seat
defining an outlet for dispensing fluid from the
reservoir. A deformable closure member overlies an open
end of the housing opposite the outlet and normally
biases a valve engageable with the valve seat to the
closed position. When selectively deformed, the closure
member is effective to move the valve to the open
position to dispense a quantity of the fluid from the
reservoir. When released, the closure member returns to
its normal condition, returning the valve to the closed
position.
~ ~91729
The present invention exhibits a large number of
features and benefits not generally found in the prior
art. For example, it can dispense fluids having an
extremely broad range of viscosities, namely, from one
centipoise to a value substantially in excess of one
million centipoises.
Furthermore, the dispenser of the invention can be
turned on and off instanteously, that is, starting and
stopping a flow of fluid occurs at substantially the
same time as operation of the valve actuator.
Additionally, fluid does not drip from the outlet nozzle
when the valve of the novel dispenser is closed but
rather, because of its unique design, the fluid is drawn
back thereby avoiding drippage of the fluid.
The dispenser of the invention can utilize low cost
materials, such as plastic. Since it utilizes a small
number of parts and requires no special seals or
springs, and because the parts are interchangeable, both
for different materials and for different sizes, it is
significantly less costly to manufacture than its prior
art counterparts.
Another significant feature of the invention resides in
its construction and manner of operation according to
which movement of an actuator used to operate the
dispenser causes simultaneous and equal movement of the
valve off its seat for dispensing the fluid. This
feature allows the dispenser to operate at very high
actuation speeds. Indeed, the dispensing of the fluid
is substantially simultaneous with the actuation of the
valve.
A
~91729
The invention utilizes no internal seals, especially
sliding seals which are particularly susceptible to
wear. Also, it uses a minimum of parts, and flow of the
fluid within the dispenser can only occur in the
direction of the outlet. As a result, the operation of
the invention is not hindered by seals which are
particularly susceptible to becoming inoperative by
being caked or gummed up with dried or partially dried
sealant or adhesive material which are commonly
dispensed products.
Various aspects of the invention are as follows:
Apparatus for dispensing precise quantities of a broad
range of fluid products, including adhesives and
sealants, regardless of orientation, comprising:
15 (1) a wand-like dispen6er portion, capable of
dispensing the fluid product in a drop-wise or
stream-like fashion, comprising a generally
cylindrical housing defining a fluid reservoir and
having a continuously open inlet for delivery of
pressurized fluid product to the reservoir for
continuously maintaining a filled reservoir and for
mai.ntaining pressure in said reservoir even when
flow of fluid out of said reservoir may have been
terminated and including a valve seat defining an
outlet for dispensing the fluid product from the
reservoir, said housing being open at an end
opposite said valve seat and terminating thereat at
a continuous annular end surface; and
a deformable resilient fluid tight closure
member overlying the open end of said housing, said
closure member having a central opening and an
oùter peripheral surface terminating in a
continuous rim, said rim being sealingly
engageable with said end surface; and
~'~91~9
5a
an elongated stem member extending through the
outlet and including a gate member at one end, said
gate member having a rounded surface for sealing
engagement with said valve seat, said stem member
being fittingly received in and extending through
said central opening of said closure member and
being fixedly and sealingly attached thereto
distant from said gate member; and
said stem member and said closure member being
responsive to an external force acting upon said
stem member in the direction of the valve seat to
thereby cause sufficient movement of said stem
member in said direction, along the axis thereof,
and deformation of said closure member to
concurrently cause said gate member to move from a
first position in sealing engagement with said
valve seat to a second position disengaged from
said valve seat thereby allowing the fluid product
to be dispensed from said reservoir through said
outlet; and
said stem member and said closure member being
responsive to the removal of said external force
such that the stem member returns to its original
position and the closure member is restored to its
original shape and, concurrently, said gate member
moves from said second position to said first
position thereby terminating the dispensing of the
fluid product; and
nozzle means attached to said housing such
that said nozzle means and said valve seat define a
dispensing chamber in which said valve gate
reciprocates between said first and second
positions and wherein when said valve gate moves
from said second position to said first position
~5 said movement, and the concurrent movement of the
stem member and the reformation of the closure
member, cause the fluid being dispensed from the
s~ ,
~9i729
5b
nozzle to rapidly reverse direction thereby causing
the fluid to be drawn back into the nozzle so as to
eliminate drippage;
(2) a pressurized source of the fluid product; and
5 (3) conduit means for supplying to said reservoir
fluid product under pressure, said conduit means
connected at one end to said pressurized source and
at its other end to the inlet opening in said
housing;
wherein, in operation, said pressurized source and said
conduit means operate to keep said reservoir filled with
fluid product under pressure.
A dispenser for dispensing precise quantities of a
broad range of fluid products, including adhesives and
sealants, regardless of orientation, comprising:
a generally cylindrical housing defining a
fluid reservoir and having a continuously open
inlet for delivery of pressurized fluid product to
the reservoir for continuously maintaining a filled
reservoir and for maintaining pressure in said
reservoir even when flow of fluid out of said
reservoir may have been terminated znd including a
valve seat defining an outlet for dispensing the
fluid product from the reservoir, said housing
being open at an end opposite said valve seat and
terminating thereat at a continuous annular end
surface; and
a deformable resilient fluid tight closure
member overlying the open end of said housing, said
closure member having a central opening and an
outer peripheral surface terminating in a
continuous rim, said rim being sealingly
engageable with said end surface; and
an elongated stem member extending through the
outlet and including a gate member at one end, said
gate member having a rounded surface for sealing
~;~917~9
5c
engagement with said valve seat, said stem member
being fittingly received in and extending through
said central opening of said closure member and
being fixedly and sealingly attached thereto
~i distant from said gate member; and
said stem member and said closure member being
responsive to an external force acting upon said
stem member in the direction of the valve seat to
thereby cause sufficient movement of said stem
member in said direction, along the axis thereof,
and deformation of said closure member to
concurrently cause said gate member to move from a
first position in sealing engagement with said
valve seat to a second position disengaged from
said valve seat thereby allowing the fluid product
to be dispensed from said reservoir through said
outlet; and
said stem member and said closure member being
responsive to the removal of said external force
such that the stem member returns to its original
position and the closure member is restored to its
original shape and, concurrently, said gate member
moves from said second position to said first
position thereby terminating the dispensing of the
fluid product; and
nozzle means attached to said housing such
that said nozzle means and said valve seat define a
dispensing chamber in which said valve gate
reciprocates between said first and second
positions and wherein when said valve gate moves
from said second position to said first position
said movement, and the concurrent movement of the
stem member and the reformation of the closure
member, cause the fluid being dispensed from the
nozzle to rapidly reverse direction thereby causing
the fluid to be drawn back into the nozzle so as to
eliminate drippage;
A
~'~9~7~9
5d
wherein said dispenser is of a wand-like configuration
and wherein, in operation, said dispenser is to be
connected to an isolated, pressurized source of fluid
product, removed from said apparatus, through a supply
conduit connected at one end to said open inlet of said
housing and at its other end to said pressurized source,
to supply said reservoir with fluid product and
maintaining the same under pressure and in a filled
state, and said nozzle means is capable of dispensing
said fluid product as individual drops or in a
continuous stream.
Other and further features, objects, advantages, and
benefits of the invention will become apparent from the
following description taken in conjunction with the
following drawings. It is to be understood that both
the foregoing general description and the following
detailed description are explemary and explanatory but
are not restrictive of the invention. The accompanying
drawings, which are incorporated in and constitute a
part of this invention, illustrate some of the
embodiments of the invention and, together with the
description, serve to explain the principles of the
invention in general terms. Like numerals refer to like
parts throughout.
R
~'~917Z9
~,
-6-
~RI~E D~SCRIPTION Q~ DRAWINGS
Fig. 1 is a side elevation view of a fluid dispensing
mechanism according to the invention and including a
diagrammatic representation of an operating and control
mechanism associated therewith:
Fig. 2 i8 a partial cross section view of the
dispensing mechanism illustrated in Fig. 1 illustrating
the mechanism in its relaxed conditions
Fig. 3 is a detail view of a component of the fluid
dispensing mechani~m;
Fig. 4 is a detail cross section view illustrating a
portion of a modified fluid dispensing mechanism;
Fig. 5 is a cross section view, similar to Fig. 2,
illustrating the fluid dispensing mechanism in its
operative condition;
Figs. 6 and 7 are detail perspective views illustrating
other embodiments of the invention:
Figs. 8 and 9 are detail cross section views
illustrating still other embodiments of the invention;
and
Fig. 10 is a side elevation view, partially cut away
and in section, illustrating still another embodiment
of the invention.
~ ~29~7~9 ` `
DETAI~ DESCRI~IQ~ QE ~ PREE~ M~Q~IM~E~
Turn now to the drawings and, initially, to Fig. l
which depicts a fluid di~penser 20 which embodies the
invention. Throughout the disclosure, the term ~fluid"
will be taken to mean any substance which ha-s the
property of flow but excluding gases and total solids
while not excluding thoge substances having solids
suspended in a liquid. Indeed, those substances which
the dispenser 20 i~ intended to dispense cover an
extremely broad range of vlscoslties, for example, from
water which has a visco~ity of one centipoise to tar-
like substances which have a viscosity of one million
centipoises, or greater.
Viewing now Pig. 2, the dispenser 20 comprises a
housing 22 which may be cylindrical, as illustrated, or
of some other suitable shape, so as to define a
reservoir 24 therein capable of containing a
pressurized fluid. The housing 22 has an inlet 26
which may be tapped to threadedly receive a suitable
fitting 28 attached to one end of a supply conduit
30, the other end of which connects to a source 32 of
the fluid which includes a suitable pump mechanism for
providing the fluid to the reservoir 24 on an as-needed
basis. One end of the housin~ 22 may be provided with
a counterbore 34, the outermost end of which may be
tapped to threadedly receive a nozzle 36. The nozzle
36 serve~ to carefully direct the flow of the fluid
dispensed from the reservoir 24 in a manner to be
described.
~9~729
At locations intermediate the reservoir 24 and the
counterbore 34, the housing 22 is provided with a
restricted region 40 in which is formed an outlet 42
defined by a valve seat 44 located immediately
downstream thereof. The end of the housing 22 opposite
the counterbore 34 may be similarly counterbored to form
a continuous annular end surface 46 which thereby
defines an annular flange 48 extending longitudinally
away from the surface 46.
As seen particularly well in Fig. 2, a closure member in
the form of a substantially hemispherical resilient dome
50 overlies the end of the housing 22 defined by the end
surface 46. The dome 50 is composed of any suitable
deformable material having a memory such that it can be
deformed by an outside force, then return to its
original configuration when that force has been
withdrawn. DELRIN brand plastic is one example of such
a suitable material, particularly for low viscosity
fluids, but other plastics, metals, or composite
materials with similar memory characteristics can be
utilized. The dome 50 has a central opening 52 and
terminates at a continuous rim 54 which is engageable
with the end surface 46.
The dome 50 is one component of an actuator mechanism
which also includes an elongated stem 56 and a suitable
fastener 58. The stem 56 extends through the opening 52
at which it is fittingly attached to the dome 50 and
extends through the reservoir 24 and through the outlet
42. At its end farthest from the dome 50, the stem 56
is provided with a gate 60 which is engageable with the
~'~9~7~9
valve seat 44 to thereby dèfine a valve for the
dispenser 20. The gate 60 may be integrally formed
with the stem 56, or it may be a separate item and
suitably bonded or fastened to the stem. It will be
appreciated that to assure the optimum operation of the
dispenser 20, the valve seat 44 must be precisely
formed and have a high degree of smoothness to assure
complete closure of the outlet 42 when the gate 60
engages the valve seat 44. The valve seat should be
composed of an inert material, examples being ceramics,
stainlesg steel, or a hard pla~t~c. As seen in Fig.
3, the ga~e may be de~irably spherical in the manner of
a bead 60A formed with a diametral bore 61
therethrough. Such beads 60A may be composed of
plastic, glass, ceramic, metal, or any other suitable
material capable of being formed to have a high degree
of roundness so as to properly and completely engage
the valve seat 44.
The dome 50 may be provided with a hollow chimney 62
extending longitudinally outwardly from an outer
surface 64 to an extreme end ~urface 66. An end of the
stem 56 opposite the gat.e 60 projects outwardly from
the dome 50 and may be threaded as at 68 to threadedly
receive the fastener 58 which may be in the form of a
nut.
The nut 58 is turned on the stem 56 until it engages
the end sur~ace 66. In the alternative, a suitable
seal member 70 may be received on the ~tem 56
intermediate the surface 66 and the nut 58 to further
prevent escape of any fluid from the reservolr 24. In
~.<Z,9~L7Z9
--10--
either event, the nut 58 is tightened down to a
sufficient extent that the gate 60 is caused to firmly
engage the valve seat 44 and such that, simultaneously,
the rim 54 engages the end surface 46. At the same
5 time, the nu~ 58 should not be tightened to such an
extent as to cause any deformation of the dome 50.
When this relationship has been achieved such that any
movement of the dome is immediate~y imparted to the
gate 60, without lost motion, it may be desirable to
suitably bond the stem 56 to the dome 50 and the nut 58
and the seal 70 together and both, in turn, to the
dome 50. With the nut 58 tightened down as indicated
in Fig. 2, it will be noted that the outer diameter of
the dome 50 ad~acent its rim 54 is substantial ly the
same as the inner diameter of the annular flange 48.
Although the annular flange 48 may not be necessary for
the purposes of the invention, it does serve as an aid
to prevent the lateral expan~ion of the dome adjacent
its rim 54 during the operation of the invention as
will be deæcribed. In another embodiment of the
invention as seen in Fig. 4, it may be desirable to
replace the annular flange 48 with an annular groove
72 to engageably receive the rim 54 of the dome 50.
In the operation of the invention, an operator can
grasp the hou~ing 22 in his hand, for example, like
holding a pencil, while an extreme end 74 of the stem
56 is manually or automatically activated. Thus, when
the stem 56 is depres~ed in the direction of an
arrow 75 as indicated in Fig. 5, the dome 50 is
deformed and this deformation allows the gate 60 to
leave its engagement with the val ve ~eat 44. The
~'~9~7Z9
pressure within the reservoir 24 caused by the source
32 is effective to cause the fluid therein to pass
through the outlet 42 and eventually through the nozzle
36 and onto an appropriate receiving surface. When the
force of the actuating mechanism is released from the
extreme end 74, the dome 50 returns to its original
po6ition and draws with it the gate 60 which again
engages the valve seat 44. The magnitude of the gate
60 and its closing velocity cause the fluid being
dispensed to rapidly reverse direction resulting in an
immediate termination of flow and elimination of
drippage of the type often a~sociated with known
devices. The visco~ity of the fluid is also an
important factor in combination with the magnitude and
velocity of the gate in achieving this desired goal.
Specifically, the greater the magnitude of the gate,
the greater its velocity and the higher the vi~cosity
of the fluid, the greater i8 the effect of terminating
flow and eliminating drippage. In this manner, there
is no dripping associated with the dispenser 20 as flow
is caused to terminate. This is true regardless of the
viscosity of the fluid and it was previously explained
that the dispenser 20 is useful for dispensing fluids
having an extremely wide range of viscositie~, namely,
within the range of one to one million plu8
centipoi~es.
The dispenser 20 i8 capable of dispen~ing part or all
of the fluid contained in the reservoir 24. It will be
appreciated that the pump mechanism at the source 32
con~tantly keeps the reservoir 24 pressurized, even
when flow of additional fluid may have been terminated.
.. l'i~917~ '
-12-
Thus, if desired, all of the contents of the dispenser
may be fully dispensed, leaving substantially no
undesired residue of the fluid in the reservoir 24.
It is also possible to evacuate all fluid from the
dispenser 20 back to the source 32, should that be
desired.
As indicated in Fig. 1, not only is the dispen~er 20
manually usable, but the stem 56 can be driven by a
variety of different mechanisms which can even be
computer controlled. Thus, a drive mechanism 76 may
be, for example~ an electr~cally operated solenoid, or
a mechanical cam, or a hydraul$cally or pneumatically
operated device. Operation of the drive mechanism may
be under the control of an appropriate computer 77 and,
using any of the~e types of drive mechanisms, the
dispenser 20 can be readily adapted for robotics usage.
The computer 77 may also control the source 32 for
regulating the amount and pressure of the fluid
provided to the reservoir 24. It is especially
attractive in this type of a use because its
simplicity of construction and operation a~sures that
it can operate for exceptionally long periods of time
between failure~, primarily as a result of the lack of
mo~ing parts such as sliding seals.
While components of the dispenser 20 other than the
dome 50 could be made of durable, long lasting, but
expensive, material~ such as stainless steel, it may
defiirable and practical to use less expensive plastic
or composite materials in it~ construction. Such
plastic or composite materials could be easily and
~'~9~7~
13
inexpensively molded. Additionally, in another
embodiment of the invention, the nut 58 may be replaced
by some other type of fastener. In one instance, for
example, as seen in Fig. 6, a cotter pin 78 may be
utilized in a known fashion in combination with a
backing washer 80 so positioned on the stem 56 to assure
that the gate 60 is engaged with the valve seat 44 when
the dome 50 is in its relaxed condition. Alternatively,
as seen in Fig. 7, a speed nut 82 may be received on the
end of the stem 56 to maintain that relati~e positioning
of the gate 60 and valve seat 44. Both of the latter
two constructions are desirable because there is no need
to tap the end of the stem 56, with a resulting savings
in cost. Indeed, it would be possible for the dispenser
to be constructed in some other fashion such that an end
of the stem 56 opposite the gate 60 is permanently fixed
to the dome 50 in a manner not requiring a fastener.
As seen in Fig. 8, a modified closure member,
specifically, cap member 84, is illustrated in place of
the dome 50, and is seen to be of concave cross section.
While the cap member 84 is not hemispherical as the dome
50 and is therefore much shallower, that is, occupies
much less distance in a direction along the stem 56
between the nut 58 and its peripheral rim 86, it has all
of the other characteristics of deformability and
plastic memory that the dome 50 has.
Yet another embodiment is illustrated in Fig. 9. In
this instance, another modified closure member in the
form of a bellows 94 replaces the dome 50. Again,
A
9~729
14
the bellows possesses the characteristics of
deformability and plastic memory which are necessary for
the successful operation of the dispenser of the
invention. It is particularly desirable for use in
those situations in which a highly viscous fluid is
being dispensed by reason of its ability to operate
through a relatively greater range of movement. This
enables the gate 60 to be moved a greater distance away
from the valve seat 44 to more readily permit flow of
fluid to the nozzle 36.
Yet another embodiment of the invention is illustrated
in Fig. 10. In this instance, a modified housing 22A
has an elongated inlet 88 disposed generally parallel to
an axis of the stem 56. A reservoir/adapter 90 integral
with the housing 22A overlies the inlet 88 and is
connected as by a conduit 92 to a source 32A for the
fluid. This design may be utilized to receive highly
viscous fluids which cannot easily be conducted through
smaller conduits and apertures. In all other respects,
however, a dispenser so modified would operate similarly
to the dispenser 20. As noted above, it may be
preferable to use the bellows 87 in this situation in
place of the dome 50.
It will also be appreciated that by using modern plastic
molding techniques, the housing 22 and dome 50, or
equivalent closure construction, may be an integral
structure. For this purpose, provision should be made
for the wall thickness in the structure opposite the
gate 60 to be somewhat reduced from the remainder of the
structure so as to enable the flexing or
` 1~9~
-15-
deformation of the nature permitted by the dome 50, cap
member 84, or bellows 87. In this construction of the
dispenser, the end of the stem opposite the gate would
be fixed to the deformable portion in some suitable
fashion, which may be in a manner as disclosed herein,
or otherwise.
While preferred embodiments of the invention have been
disclosed in detail, it should be understood by tho~e
skilled in the art that various other modifications may
be made to the illustrated embodiments without
departing from the scope of the invention as described
in the speciflcation and defined in the appended
claims.
