US 3622050 A
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Description (OCR text may contain errors)
United States Patent  Inventors Daniel D. Acton;
Orris E. Mumford, both of Lancaster, Ohio [21 Appl. No. 798,892  Filed Feb. 13, 1969  Patented Nov. 23, 1971 I 7 3 Assignee Anchor Hocking Corporation Lancaster, Ohio  METERED COMPOUND APPLYING NOZZLE 4 Claims, 3 Drawing Figs.
52 vs. c1 222/309, 222/334  Int. Cl ..G01t11/06  Field of Search 222/309, 334, 333, 255, 263, 504, 380, 387; 239/4l2  References Cited UNITED STATES PATENTS 2,142.08! l/i939 Olive 222/387 2,818,999 1/1958 Miller 222/387 x 3,160,331 12/1964 Trumbull et al. 222/309 3,227,325 1/1966 Bates 222/334 3,366,288 l/l968 Goldschein 222/504 Primary ExaminerSamuel F. Coleman Assistant Examiner-L. Martin A!!0rneyN0rman N. Holland 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 ofa control needle a predetermined amount while the compound is forced through the orifice by a discharge piston as it displaces the predetermined volume ofcompound in the charge chamber.
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 offluid 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:
F 1G. 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 l 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. I) 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. I, the closure 1 in which an annular gasket 4 (FIG. 3) is to be formed is shown mounted on a rotating support 7. The nonle 6 is positioned above the closure 1 with its axis arranged at the desired angle for positioning the gasket material 5 in the comer 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 sufiicient 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 I], 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 l 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.
H0. 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 within the charge chamber or cavity of predetermined volume.
A typical gasket formulation consists of a fluid plastisol such as a combination ofa 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 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 ofcircular 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 com ound being handled of the nozzle timing system.
This ma es 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.
Having thus described our invention, we claim:
I. 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.