U.S. patent number 3,622,050 [Application Number 04/798,892] was granted by the patent office on 1971-11-23 for metered compound applying nozzle.
This patent grant is currently assigned to Anchor Hocking Corporation. Invention is credited to Daniel D. Acton, Orris E. Mumford.
United States Patent |
3,622,050 |
Acton , et al. |
November 23, 1971 |
METERED COMPOUND APPLYING NOZZLE
Abstract
A nozzle for injecting liquid into articles and particularly for
injecting relatively viscous liquids including plastisols or other
flowable compounds such as are used to form gaskets in hollow
closure shells. The nozzle injects a precisely predetermined volume
of flowable material at a controlled rate so that a gasket ring or
other element may be formed with a precise degree of overlap. The
volume is controlled by admitting a predetermined amount of the
liquid compound into a charge chamber which is then closed off from
the compound source. This charge is then injected through the
nozzle orifice by the opening of a control needle a predetermined
amount while the compound is forced through the orifice by a
discharge piston as it displaces the predetermined volume of
compound in the charge chamber.
Inventors: |
Acton; Daniel D. (Lancaster,
OH), Mumford; Orris E. (Lancaster, OH) |
Assignee: |
Anchor Hocking Corporation
(Lancaster, OH)
|
Family
ID: |
25174524 |
Appl.
No.: |
04/798,892 |
Filed: |
February 13, 1969 |
Current U.S.
Class: |
222/309;
222/334 |
Current CPC
Class: |
B29C
41/20 (20130101); B29C 45/461 (20130101); B29C
70/80 (20130101); B29C 31/041 (20130101); B29C
45/53 (20130101); B29C 31/063 (20130101); G01F
11/06 (20130101); B29C 41/045 (20130101); B29L
2031/565 (20130101); B29C 33/36 (20130101) |
Current International
Class: |
B29C
41/04 (20060101); B29C 41/02 (20060101); B29C
45/46 (20060101); B29C 45/53 (20060101); B29C
70/00 (20060101); B29C 70/80 (20060101); G01F
11/06 (20060101); G01F 11/02 (20060101); B29C
31/06 (20060101); B29C 31/04 (20060101); B29C
41/20 (20060101); B29C 33/36 (20060101); B29C
33/00 (20060101); G01f 011/06 () |
Field of
Search: |
;222/309,334,333,255,263,504,380,387 ;239/412 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Coleman; Samuel F.
Assistant Examiner: Martin; L.
Claims
Having thus described our invention, we claim:
1. An improved injection nozzle for viscous liquid material to form
a line of the liquid of predetermined cross section and length
comprising the combination of a nozzle head, an injection orifice
in said nozzle head, a cavity in said nozzle head communicating
with said orifice, an inlet communicating with said cavity and
adapted for being connected to a source of said material for
admitting the material into the cavity, valve means for opening and
closing said inlet, a remotely controlled drive for said valve
means, an injection plunger movably mounted within said cavity for
forcing the material through said orifice, a control needle for
said orifice passing through said cavity, remotely controlled drive
means for moving said control needle to open and close said
orifice, means for adjusting the opened position of said control
needle to control the line cross section, remotely controlled drive
means of adjustable force coupled to said plunger for moving it a
predetermined distance within said cavity for forcing a
predetermined volume of the material through said orifice to
control the flow rate, and means for adjusting the predetermined
distance which the plunger is moved to control the volume of liquid
injected.
2. The nozzle as claimed in claim 1, in which said means for
opening and closing said inlet comprises a fluid operated
valve.
3. The nozzle as claimed in claim 1, in which said plunger drive
means comprises a fluid motor including means for adjusting the
distance of plunger movement.
4. The nozzle as claimed in claim 1 in which said means for moving
said nozzle control needle comprises a fluid motor.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a compound applying nozzle of the
type used to inject a predetermined volume of liquid plastic or
other materials onto or into objects at a controlled rate. One
particular application, for example, which is in frequent use is
the formation of circular gaskets for container closure caps. In
such closure caps, a circular gasket is formed within a hollow
shell by spinning the shell while injecting a line of gasket
material around the turning closure shell. In order to assure a
uniformly shaped gasket, it is necessary for its volume to be a
predetermined amount and for the line or thread of plastic to meet
with insignificant overlap. Thus, where a gasket may be applied to
a closure shell during three turns of the shell, it is desirable
that the injecting nozzle be capable of applying three full turns
with an insignificant overlap or underlap at the finishing
point.
Prior nozzles of this general type have been used and the volume
and overlap control have been obtained by controlling the gasket
compound feed pressure and by controlling the feed time. Such an
arrangement has been generally satisfactory where the gasket cross
sections themselves and the gasket volume have not been critical
and good prior results have also been obtained for gasket materials
of relatively low viscosity. Considerable trouble has been
encountered, however, in forming many types of gaskets which are to
be subsequently molder or formed into a precise shape and where the
gasket material which is being used for the gaskets may also be
relatively viscous. An example of such a process is in the
manufacture of closure caps having a substantial portion of the
gasket positioned at the cap skirt and particularly where this
portion is shaped with or without container engaging threads.
SUMMARY OF THE INVENTION
The compound applying nozzle of the present invention injects a
precisely predetermined volume of material by using a closed charge
or injection chamber in combination with an injecting piston which
is driven through a stroke of controlled length during the
injecting operation. Thus, after the injecting piston is withdrawn
to its raised position a feed valve opens to admit the liquid
compound into the charging chamber. This feed valve is then closed
so that the incompressible gasket material is confined within a
charge chamber of predetermined volume. A control needle which has
closed the nozzle orifice is now opened a precisely controlled
amount while the feed plunger is activated by its own drive piston
so that it moves through a stroke of predetermined length under
controlled pressure. This forces the predetermined volume of
injection compound through the nozzle orifice at a controlled rate.
Since the movement of the control needle and the feed plunger and
the plunger driving pressure are adjustable, the volume and the
flow rate of the injected compound may be preset for a particular
operation and for an injected compound of a particular desired
viscosity.
Accordingly an object of the invention is to provide an improved
method and means for injecting a predetermined volume of fluid at a
controlled rate.
Another object of the present invention is to provide an improved
injection nozzle particularly adapted for handling relatively
viscous fluids and for injecting a predetermined volume of such
fluids at a controlled rate.
BRIEF DESCRIPTION OF THE DRAWING
A preferred embodiment of the invention has been chosen for
purposes of illustration and description and is shown in the
accompanying drawings, forming a part of the specification
wherein:
FIG. 1 is a side elevational view in section of a preferred
embodiment of a nozzle in accordance with the present invention
illustrated in use forming an annular gasket in a rotating closure
shell;
FIG. 2 is a similar side elevational view in section of the nozzle
of FIG. 1 illustrating the position of its components during the
fluid injection; and
FIG. 3 is a cross-sectional view of a typical closure shell having
an at least partially formed gasket of the type injected by the
nozzle of FIGS 1 and 2.
DESCRIPTION OF A PREFERRED EMBODIMENT
A preferred embodiment of an injection nozzle in accordance with
the present invention is illustrated in the drawings and will be
described as used to form an annular gasket in a closure of the
type used to seal glass and other containers. It is clear that the
nozzle is useful for numerous other purposes.
Such a closure, for example, is illustrated at 1 in FIG. 3 having a
top portion 2 with a depending skirt 3. A gasket 4 is formed on
portions of the cap top 2 or skirt 3 for forming a seal with a
container. The closure cap 1 illustrated shows the gasket 4 with a
generally curved surface resulting from the application of a
predetermined volume of gasket material such as a plastisol
injected into the shell. Such a gasket is preferably formed by
rotating the closure 1 one or more revolutions while injecting the
gasket material 5 (FIG. 1) from the nozzle 6 and while controlling
both the overall volume of the material and its rate of flow into
the closure 1. In order to have uniformly shaped gasket, the mount
of overlap or underlap resulting at the completion of the final
turn must be minimized and the control of the compound volume and
flow rate achieves this by causing the compound flow to end at the
desired position of the closure 1.
In FIG. 1, the closure 1 in which an annular gasket 4 (FIG. 3) is
to be formed is shown mounted on a rotating support 7. The nozzle 6
is positioned above the closure 1 with its axis arranged at the
desired angle for positioning the gasket material 5 in the corner
of the closure 1 between the top 2 and the skirt 3. The nozzle 6
comprises a head portion 8 including the nozzle outlet or orifice 9
formed adjacent to a hollow fluid charge cavity 10. This cavity 10
is supplied with the gasket material 5 through an inlet 11 and a
feed valve 12 including a control stem 13. The upper portion of the
charge cavity 10 is closed off by the working surface 14 of a fluid
injection plunger 15 which is driven by a piston 16 in a drive
cylinder 17.
The feed valve 12 also includes a power piston 18 and an associated
cylinder 19 for moving the feed valve between its opened and closed
position. The piston 18 is operated by the application of
compressed air or other hydraulic fluid fed through the spaced
ports 20 and 21 which are alternatively coupled to the hydraulic
source and to an exhaust port in accordance with the direction in
which the feed valve piston 18 is to be moved. In FIG. 1 the piston
18 is shown in its open position permitting the gasket compound 5
to completely fill the charge cavity 10 as the compound 5 flows
inwardly past the feed valve 12 under its own supply pressure. The
feed valve 12 will remain open for a sufficient period to insure
the complete filing of the charge cavity 10.
When the feed valve 12 is thereafter closed (FIG. 2) it is seen
that the charge cavity 10 is a fully enclosed cavity whose
confining walls include those in the nozzle head 8 as well as the
walls of the supply inlet 11, the injection plunger 15 and the stem
13 of the feed valve 12. The feed valve 12 may be opened and closed
by suitable timing means mounted on the apparatus which handles the
closures 1 and the valve 12 so timed that it is opened for a
suitable period prior to the compound injection cycle. This period
during which the feed valve 12 is opened is not critical as long as
it is opened long enough to ensure a complete charge in cavity 10
and as long as it is thereafter closed prior to the commencement of
the compound injection into closure 1 by the plunger 15.
The movement of the plunger 15 is controlled by spaced stop means
23 and 24 of which the upper one 23 is made adjustable to determine
the length the plunger stroke and to thus control the volume of the
compound injected by the nozzle 6. Movement of the plunger is
initiated by the application of a hydraulic fluid to the inlet port
25 while the outlet port 26 is coupled to a suitable exhaust. By
controlling the pressure of the hydraulic fluid supplied through
the inlet 25 the piston force may be set and held constant and the
rate of movement of the plunger and thus the rate of injection of
the nozzle 6 may be set by the distance which the nozzle control
needle 27 is opened. The control needle 27 also is preferably moved
between its opened and closed positions by a drive piston 28
coupled to its upper end 29 just beneath the needle stop member 30
A hydraulic drive force is alternatively supplied to opposite ends
of this piston 28 through the spaced ports 31 and 32. The port 32
for opening the needle may be coupled to the same source of
hydraulic fluid as the port 25 for operating the plunger 15 since
the needle may be opened simultaneously with the initiation of the
plunger movement of it may be separately controlled. In order to
give a precise control of the compound flow rate, the open position
of the needle 27 is adjusted by the threaded stop screw 30 mounted
at the top of the injection nozzle 6. This screw stop 30 is
adjusted to give a fine control for the opened position of the
needle 27 thereby giving a sensitive and precise control of the
injection compound or fluid flow rate.
FIG. 2 shows the above-described elements of the nozzle 6 in their
injection position. Thus the feed valve 12 has been moved to its
closed position thereby confining the gasket material 5 within the
charge chamber or cavity 10 of predetermined volume.
A typical gasket formulation consists of a fluid plastisol such as
a combination of a vinyl resin with a liquid plasticizer. Such
formulations characteristically have the fluid characteristic of
being incompressible so that the preset movement of the nozzle
plunger 15 results in an injection of a correspondingly preset
volume of the liquid plastic.
The injection plunger 15 in FIG. 2 is shown in its fully injected
position as it has been driven forwardly against the nozzle lower
stop 24. The nozzle control needle 27 is shown in its rearward or
opened position having been moved against its position stop 30 by
the application of hydraulic fluid under pressure to its driving
piston 28.
A packing means is provided for the stem 13 of the feed valve 12
which comprises, in its preferred form, a group of circular packing
washers 34 preferably formed of Teflon and of the general type
known as chevron washers positioned between end washers 35 and 36.
Washers 34 have a V-shaped cross section and are packed into
sealing relationship with the valve 12 stem and body by an
adjustable threaded packing nut 37.
A similar arrangement of packing washers 38 together with a
threaded packing nut 39 are used to seal the feed plunger 15.
It will be seen from the above that the time of closing the nozzle
orifice 9 by the control needle 27 is not critical and will not
effect the volume of plastisol which is injected into the closure
cap 1 as this volume is controlled by the amount of plunger
movement. The cam or other control system need only be set to close
the control needle 27 and to return the plunger 15 to its rearward
position prior to the reopening of the feed valve 12 for the next
injection cycle. It is also clear, therefore, that this injection
nozzle operates relatively independently of a precise timing
arrangement and thus is independent of minor variations in such
timing arrangements which invariably otherwise occur.
It will be seen that an improved compound or liquid injection
nozzle has been provided which is particularly useful for inserting
or injecting predetermined volumes of such compounds at controlled
injection rates. The controlled volume and rates are obtained by
relatively simple and basically physical adjustments of the nozzle
elements which permits them to be precisely set and which permits
them to operate continuously at high speeds without significant
variations. These adjustments are independent of the supply
pressure of the compound to the nozzle and also of minor changes in
the viscosity of the compound being handled of the nozzle timing
system.
This makes the new nozzle particularly useful in a number of
operations handling relatively viscous materials and in particular
it makes it useful in injecting viscous plastics such as plastisols
and other plastic formulations of relatively high viscosity such as
are employed in forming sealing gaskets for closure caps and other
articles.
As various changes may be made in the form, construction and
arrangement of the parts and in the steps of the method herein
without departing from the spirit and scope of the invention nd
without sacrificing any of its advantages, it is to be understood
that all matter herein is to be interpreted as illustrative and not
in a limiting sense.
* * * * *