Note: Descriptions are shown in the official language in which they were submitted.
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NUTATING ORIFICE DISPERSION APPARATUS
FIELD OF THE INVENTION
This invention i5 directed to a means by which
materials such as a medium to high viscosity, thixotropic
or fiber filled materials can be applied to a substrate.
More particularly, this invention is directed to an
nutating orifice dispersion apparatus for use in combina-
tion with a robot to form a dispensing system in which a
ribbon o a material having a variable width and thickness
can be applied to a substrate from a distance of between
about 1 to 6 inches and can be applied at various angles
relative to the substrate and even applied to an overhead
`` surface.
BACKGROUND OE_THE INVENTION
The use of adhesives and sealants in the automo-
tive indu tries is becoming increasingly important.A~hesives and sealants are used in the assemblies of such
hem-flanged parts as doors, decks and hoods. For example,
sealing materials can be used in conjunction with more
`~ conventional spot-weldinq techniques. The sealant is irst
applied and then the sheet metal is welded through the
~ sealant. Such a combined approach has allowed the-distance
; between spot welds to be increased while reducing the
number of welds. Some manufacturers, moreover, have
eliminated the welding altogether by employing structural
adhesives.
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However, the use of adhesives has presented
several distinct disadvantages. Unless carefully applied,
the use of adhesives and sealants can be a messy operation
requiring manual cleanup. If too much adhesive is applied
or if it is not properly covered in the hemming operation,
it can contaminate the electrophoretically deposited paint
primer baths that are necessary prior to painting. Addi-
tionally, excess adhesive can also contaminate hemming
dies. The flanges and method for joining parts must be
structured to avoid wiping the adhesive from the part once
the adhesive is applied thereto. It is not possible to
paint over some adhesives and sealants, amplifying the need
for accurate dispensing of these materials onto the specif-
ic component piece.
Heretofore, the manual application of adhesives
and sealants to assemblies has been found to be generally
impractical because of the high throughput and hi~h accura-
cy required. As a result, the present automotive manufac-
turing environment places exacting demands on systems that
can automatically apply adhesives and sealants.
Adhesives and sealants must be applied accurate-
ly, along the right bead path, in the required cycle time,
in the precise volume required, and with the proper cross
section. Otherwi.se, incorrect bonding or squeezing or bead
placement will occur.
A dispensing system must be designed to handle
the throughput requirements of the production assembly line
as well ag the geometry of the workpiece. Cycle times can
be as ~hort as 3 to 4 seconds for dispensing material
around the entire perimeter of a door. At constant
dispensing-head velocity, an a& esive or sealant must be
delivered at Gonstant pressure and 10w to produce a
uniform bead.
It has been found that a robotic dispensing
yst~m can generaily accommodate the aforementioned re-
quirements and substantially alleviate the above-enumerated
disadvantages of adhesive use. However, significant
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limitations are still found in the actual adhesive dispens-
ing system.
It is therefore an object of this invention to
provide a nutating orifice dispersion apparatus for the
application of a pattern of adhesive material or the like
in any direction without reorienting the nozzle apparatus.
The flow rate is adjusted by varying the pressure supplied
to the noz7.1e. The pa~tern width is varied by adjusting
the distance between the nozzle and the work surface.
SUMMARY OF THE INVENTION
The nutating orifice dispersion apparatus of this
invention is adapted for use in combination with a robot
dispensing system including an industrial manipulator and a
material conveyance system for delivering the adhesive
material or the like from a storage point to the nozzle
whereupon the material is applied to the workpiece as
desired. The nutating orifice dispersion apparatus of this
invention has a dispensing tube means with a first end for
receiving materials to be dispersed thereinto and a second,
nozzle end from which the material is dispersed. A support
means is provided in which the dispensing tube means is
disposed. A first mounting means supports the dispensing
tube means at a location proximate the first end. The
first mounting means is mounted in the support means for
rotational movement about a first axis. The first mounting
means supports the dispensing tube at a location proximate
the first end the for oribital movement of the first end
about the first axis. A second support means compliantly
supports the dispensing tube means at a location proximate
the second or nozzle end thereof. In other words, first
end of the dispensing tube is not rotating but rather it is
orbiting the first axis. Finally motive means are opera-
tively associated with the first mounting means for affect-
ing the rotational movement of the first mounting means
about the fir~t axis.
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BRIEF ~ESCRIPTION OF THE DRAWINGS
The above, as well as other features and
advantages of the present invention, will become apparent
through consideration of the detailed description of the
preferred embodiment of this invention in conjunction with
the several drawings in which:
Figure 1 is a'somewhat schematical representation
of a robot dispensing system incorporating the nutating
orifice dispersion apparatus all according to the teachings
of this invention;
Figure 2 is a sectional view of the nutating
orifice dispersion apparatus according to this invention;
Figure 3 is a sPctional view along lines III III
of Figure 2 illustrating the rotational mounting means
through which the nutational movement is effected at th~
dispersion orifice of the apparatus of this invention; and
Figure 4 is a plan view of the dispersion pattern
of material deposited by means of the nutating oriflce
dispersion apparatus of this invention.
20DETAILED DESCRIPTION OF THE INVENTION
A robotic dispensing system which incorporates
the nutating orifice dispersion apparatus (NODA) by which
materials such as high ~iscosity, thixotropic or fiber
filled materials can be applied to a substrate is schemati-
cally illustrated in Figure 1 and indicated by the refer-
~: ence character 11. The robotic system 11 includes a robot
13 in communication with ~ robot control means 15 for
applying the appropriate commands to effect the desired
~: mo~ement of the robot 13. A material supply means such as
container 17 holds the material to be dispersed by means of
the robot system. The material supply means 17 is in
communication via a conduit 19 with the nutating orifice
dispersion apparatus (NODA) 21. A pump and fluid flow
control apparatus which is schematically indicated at 23,
insures that the appropriate flow of material is maintained
. to the N~DA nozzle 21. A workpiece 25 is positioned within
the work envelope of the robot 13 for the application o
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52,569
the desired materiOl thereto. The worXpiece can be placed
into position by a conveyor means or the like. It should
be appreciated that the present system is not limited to a
specific type o robot and t~a~ the robot shown in Figure 1
is for illustrative purposes only. The robot 13 includes a
base portion 27 which would typically be secured to the
floor of the work area, and at least a first arm 29 rotat-
ably and pivotably mounted with respect to the base portion
27, a second arm 31 rotatably mounted about one end of the
arm 29 and a wrist 33 mounted onto the cantilevered end of
th~ arm 31. The N~DA nozzle 21 would be fixedly attached
to the wrist 33 for manipulation thereby. Such a wrist
preferably provides ~everal degrees of freedom for the
manipulation of the NODA nozzlP 21. The conduit means 19
convey the material from the material supply 17 by way of
the pump and flow control means 23 to the NODA nozzle 21.
Considering Fi~ures l through 3, the operating
principles of the NODA nozzle can be readily appreciated.
The NODA nozzle generally indicated by the reference
character 21 includes a drive means housing 35 which has at
the upper end thereof a mounting means 37 adapted to permit
the NODA nozzle 21 to be removably interconnected to the
wrist 33 of the robot 13. At the lower end 39 of the drive
means housing 35 a support means 41 depends downwardly
therefrom and provides a housing which supports the adhe-
sive disp~nsing tube 43. The dispensing tube means 43 has
a fir~t end 45 for receiving therein the materials to be
conveyed through the dispensing tube and dispersed there-
from and a second or nozzle end 47 from which the material
is ultimately dispersed and a center portion 49 disposed
thereinbetween. The upper portion 45 of the dispensing
tube 43 is supported by an upper support means Sl. The
nozzle end 47 of the dispensing tube means 43 is supported
by a diaphragm 53 which encloses the bottom portion of the
lower support means 41. The dispensing tube 43 is main-
tained in that diaphragm about a first axis 55. The
diaphragm 53 can be made of stainless steel or similar
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material which provides a relatively ixed yet flexible
support for the dispensing tube 43. This diaphragm facili-
tates the nutating movement of the nozzle end 47 of the
dispensing tube 43. The first end 45 of the dispensing
tube means 43 is in communication with a delivery tube
means 19 by means of a high pressure~ flexible tubing member
59. A housing 57 which is generally a continuation of the
lower housing portion 41 extends above the upper support
means 51 and encloses the high pressure flexible tubing 59.
At the upper portion of the housing 57 is an inlet fitting
61 which provides a threaded joint by which the delivery
tube means 19 for the material to be deposited is connected
to the system. Thus the high pressure tubing 59 is inter-
connected between the inlet fitting 61 and the first end 45
of the dispensing tube means 43.
The housing 35 is a generally rectangular struc-
ture which encloses a synchronous motor 63, preferably a
24,000 rpm synchronous motor. The output shaft 6S of the
synchronous motor has a spur gear 67 mounted thereon which
is in communication with a second spur gear 69 by w~ich the
orbiting motion of the first end 45 of the dispensing means
43 is effected. The second spur gear 69 is mounted for
rotational movement about the axis 55 within the upper
support mean~ 51 by means of bearings 71 and support
structure portion 73 of the support means 51.
The nutating movement of the nozzle portion 47 of
the dispen~ing tube means 43 is effected by the orbital
movement of the first end 45 of the nozzle means. The
fir~t end 45 of the dispensing tube means 43 is mounted in
the spur gear 69 so as to orbit about the axis 55. An
offset bore indicated at 75 is provided in the spur gear
69. The first end 43 of the dispensing tube means 45 is
mounted within the bore 75 by means of bearings 77. As the
~pur gear is rotated about the axis 55, the first end 45 of
the dispensing tube means 43 orbits the axis 55. It should
be appreciated that no rotational movement is being
i inparted to the dispensing tube 43 as it orbits about the
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axis 55, rather t~e first end 45 is moved in an orbital
path or a continuous displacement thereof about a fixed
axis defined by the rotational movement of the spur gear
69. As described previously, the diaphragm 53 supports the
dispensing end 47 or nozzle and facilitates the nutational
displacement thereof. A sized output nozzle as at 85 has a
bore 87 of a predetermined diameter which is smaller than
the inside diameter of the dispensing tube. Several such
nozzles can be provided, each having a unique bore diame-
ter, for selected insertion into the nozzle 47.
The NODA nozzle of this invention isomnidirectional and there is no need to orient the nozzle
with respect to the workpiece because the nozzle can be
maintained a predetermined distance from the workpiece,
whereas conventional extrusion devices require physical
contact with the workpiece. This NODA apparatus provides
good seam penetration because of the high impact velocity
and high inertia of a cylindrical stream as opposed to the
conventional techniques of material application. For
example, devices using a spray technique emit droplets
which are characterized by a high surface tension to mass.
As a result, these droplets tend to bounce off rather than
penetrate the same area or workpiece. There is no
overspray as with conventional devices. The operator is
specifically able to place the material at a desired
location on the workpiece. As shown in Figure 4 the NODA
provide~ a stable fan with a flow rate change that can vary
from 5 to 1. The upper limit of the flow rate is con-
trolled by the maximum pressure which can be delivered to
the nozzle. The lower limit of the flow rate is controlled
by the minimum exit velocity needed to maintain pattern
width. The nutating movement of the nozzle 47 as effected
by the orbital movement of the ~irst end 45 o the dispens-
ing tube means 43 eliminates the centrifugal components of
the material being dispensed at the orifice. This main~
tains the dispersion angle regardless of the flow rate of
the material through the dispensing tube means. Accord-
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ingly, a ~table circle pattern of dispensed material isdeveloped regardless of the flow rate. Because of these
uni~ue features, the NODA nozzle can be utilized to effec-
tively penetrate seams and workpieces where appropriate
even when the nozzle is disposed in an upside-down rela-
tionship with the workpiece. This is due to the fact that
the NODA delivers a high mass of material with low surface
tension. The NODA nozzle combines the most advantageous
features of spray deposition and extrusion techniques in
the application of an adhesive material to a workpiece and
the penetration of the adhesive material into the seam o
two abutting workpieces.
It is expected that the radius of the orbit of
the first end ~5 of the dispensing tube means 43 about the
fixed axis 55 in relationship to the diameter of the nozzle
portion 47 is approximately 20% greater than the diameter
of the nozzle exit oriice. The cone angle as shown in
Figure 2 would be approximately 45. The nozzle would be
positioned approximately 4 inches above the work surface
and the nutating motion of the nozzle about the fixed axis
would dispense a ribbon of material as illustrated in
Figure 4 of approximately 5/8 inch in width. The pattern
width changes are minimal even with increased flow rate or
exit velocity of material due to the control of the dis-
tance between the exit point of the nozzle and the work-
piece and as indicated above the elimination of the
centrifugal component of the orifice maintains the disper-
sion angle regardless o the flow rat~.
What has been described is a nutating orifice
dispersion apparatus by which materials such as medium to
high vi6cosity, thixotropic or fiber filled materials can
be applied to a substrate. The dispersion pattern is
typically a ribbon of variable width and thicXness. The
pattern is applied to the sl~bstrate from a distance of
between about 1 to 6 inches and can be applied at various
angles to the substrate and even applied to an overhead
surface. The pattern can be applied in any direction
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without reorienting the nutating orifice dispersion
apparatus of this invention. The material flow rate is
simply adjusted by varying the pressure supplied to the
NODA. The pattern width is varied by adjusting the dis-
tance between the NODA and the work surface. Thus the flowrate through the NODA can be modulated at will without
effecting the ribbon pattern width. This advantage is key
to the robotic application o~ sealant in that the speed of
the arm may not be constant throughout the dispensing cycle
and the material flow rate needs to be varied correspond-
ingly in order to maintain ribbon uniformity.
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