WO2000047388A1

WO2000047388A1 - Method and device for manufacture of an aerosol dome or other actuator

Info

Publication number: WO2000047388A1
Application number: PCT/AU2000/000088
Authority: WO
Inventors: Johann Friedrich Jaeggi; Karl James Wilkinson
Original assignee: BISHOP MANUFACTURING TECHNOLOGY Ltd; Precision Valve Australia Pty Ltd
Current assignee: BISHOP MANUFACTURING TECHNOLOGY Ltd; Precision Valve Australia Pty Ltd
Priority date: 1999-02-12
Filing date: 2000-02-11
Publication date: 2000-08-17
Anticipated expiration: 2001-08-12
Also published as: AUPP864999A0

Abstract

A method and device for manufacturing an injection moulded plastic dome (or other actuator) for an aerosol valve and container. The method comprises the steps of inserting a removable core pin, said core pin being shaped to form an aperture in the plastic dome for receiving a nozzle insert, into a mould cavity adapted to form the dome; injecting melt into the mould cavity to form the dome; removing the core pin from said mould cavity; and thereafter inserting a preformed nozzle insert from outside the mould into the aperture whilst the dome remains in the mould cavity, whereby the nozzle insert and dome are integrated. The device comprises at least one mould cavity moulding said dome; and at least one means for injecting melt into said cavity; and further having at least one means for removably inserting a core pin into the mould cavity to form the mould aperture, and at least one means for inserting a preformed nozzle insert from outside the mould into said aperture after the core pin is removed from the cavity.

Description

METHOD AND DEVICE FOR MANUFACTURE OF AN AEROSOL DOME OR OTHER ACTUATOR

TECHNICAL FIELD

This invention relates to a method and device for manufacturing a plastic dome or other actuator for an aerosol valve by plastic injection moulding and which includes a separate nozzle insert integral therewith.

BACKGROUND

In aerosol valve manufacture it has been well known to provide a relatively small-in- diameter plastic actuator seated on the aerosol valve stem, the actuator usually having a tubular opening and passage leading from the valve stem to a nozzle insert in the actuator outlet. The actuator is adapted for actuation by the finger of a user in order to dispense the aerosol product contained within the container to which the aerosol valve is attached. In such an arrangement the top of the aerosol container and the actuator are generally covered with a separate plastic cover cap for safety and to prevent accidental discharge of the aerosol product during storage and handling.

More recently in aerosol valve manufacture, the separate cover cap member has been discarded and replaced with a plastic dome (helmet, overcap or delivery head) which also includes an internal tubular portion, a finger actuatable portion and a nozzle insert integrally moulded therein, or alternatively inserted by interference fit into the dome subsequent to moulding of the dome and removal of the dome from the mould. When the finished dome is fitted to the top of the container, it is seated on the valve stem and is adapted for actuation by the finger of a user in order to dispense the aerosol product in a conventional manner.

The method of formation of an aerosol dome-nozzle insert assembly (or aerosol actuator-nozzle insert assembly) which involves a nozzle insert to be interference- fitted to an already moulded dome or other actuator requires a separate secondary assembly operation and machine, and adds cost to the overall manufacture. Furthermore, since the two parts may be interference fitted after the parts are cooled, tolerances are small and minute variations in the behaviour of the thermoplastic in the moulding process may result in non-secure fits.

A number of moulding mechanisms have been devised to form and assemble an aerosol dome or other actuator and nozzle insert in a single moulding operation. US Patent No. 4,741 ,088 (Ramella) discloses a method of moulding and assembling an aerosol delivery head, in which the delivery head and nozzle insert are integrally formed in the same moulding operation such that they are connected by a thin flexible strip of plastic. Subsequent to the moulding operation, a portion of the mould is retracted, i.e. the mould is opened, urging the nozzle insert to be moved about the flexible strip of plastic and placed into its intended position at the outlet opening of the delivery passage formed in the aerosol delivery head. US Patent No. 5,378,422 (Musiel et al.) discloses a moulding mechanism for simultaneously moulding an aerosol dome and nozzle insert. The mould is opened and the nozzle insert is separated from its forming position and repositioned and inserted into the discharge outlet of the aerosol dome.

A disadvantage of such mechanisms is that, as the nozzle is formed in the same mould as that of the dome, it is generally costly and time consuming to make injection moulds to provide domes having nozzle inserts with different spray characteristics. Further, in such a system, the dome and nozzle insert will generally be formed of the same plastic so that nozzle configurations and cost economics are not necessarily maximised.

The present invention is intended to ameliorate the manufacture of injection moulding plastic aerosol domes and other actuators.

SUMMARY OF THE INVENTION

It should be understood that use of the term "dome" hereinafter is intended to include any type plastic aerosol valve actuator containing a nozzle insert. In a first aspect the present invention is a method for manufacturing an injection moulded plastic dome for an aerosol valve and container, said method comprising the steps of:

(i) inserting a removable core pin into a mould cavity adapted to form said dome, said core pin being shaped to form an aperture in the plastic dome for receiving a nozzle insert;

(ii) injecting plastic melt into said mould cavity to form said dome;

(iii) removing said core pin from said mould cavity; and

(iv) inserting a separately-formed nozzle insert from outside the mould into said aperture within said dome whilst it remains in the mould cavity, whereby said nozzle insert is integrated with said injection moulded dome.

Preferably said preformed nozzle insert is inserted into the dome aperture shortly after the injection of the melt and upon the initial solidification of the dome. Upon cooling of the dome, the aperture shrinks about the insert to firmly retain it in place. Most preferably, the nozzle insert is inserted into the dome aperture within ten seconds after the injection of the melt.

In a second aspect the present invention is a device for injection moulding a plastic dome for an aerosol valve and container, said device comprising: at least one mould cavity for moulding said dome; and at least one means for injecting melt into said cavity; characterised in that said device further comprises at least one means for removably inserting a core pin into said mould cavity to allow for the formation of an aperture within said dome being moulded, and at least one means for inserting a preformed nozzle insert into said dome aperture while the dome is still within said mould cavity and after said core pin is removed therefrom after said melt has been injected into the mould cavity, whereby said nozzle insert is integrated with said injection moulded dome. Preferably the device inserts the nozzle insert into the dome aperture shortly after the injection of the melt, most preferably within ten seconds thereafter.

Preferably the means for removably inserting said core pin comprises a first actuator means.

Preferably the means for inserting the preformed nozzle insert comprises a second actuator means.

Preferably the first actuator means is mounted on a shuttle carriage for movement relative to the mould cavity.

Preferably the second actuator means is mounted on a shuttle carriage for movement relative to the mould cavity.

Preferably the preformed nozzle insert is delivered to the second actuator means from a hopper delivery system adapted to hold a plurality of such performed nozzle inserts.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of a non-limiting example with reference to the accompanying drawings.

Figure 1 is a perspective schematic view of a first embodiment of the injection moulding device of the present invention, wherein a removable core pin is shown inserted into the mould.

Figure 2 is a plan view of the injection moulding device shown in Figure 1.

Figure 3 is a plan view of the injection moulding device shown in Figure 1 wherein the removable core pin is shown removed from the mould and the shuttle carriage carrying the core pin is shown being moved linearly away from the mould cavity. Figure 4 is a plan view of the injection moulding device shown in Figure 1 wherein a preformed nozzle insert is being inserted into the moulded dome.

Figure 5 is an enlarged view of the preformed nozzle insert being inserted into the moulded dome as shown in Figure 4.

MODE OF CARRYING OUT INVENTION

Figures 1-5 depict one embodiment of an injection moulding device 1 which comprises a mould cavity 2 for forming a dome which is adapted to be fitted to a conventional aerosol valve and container. For reasons of clarity the injection moulding device 1 is shown in schematic view with detail of the injection melt delivery apparatus removed, and only detail of the mould cavity, and nozzle insertion means is shown. Various supports, journals, bearings, control units and hydraulic and/or pneumatic delivery systems, well-known to those skilled in the art, have been omitted from the figures.

The injection moulding device 1 has a conventional well-known means for delivering plastic melt (not shown) into mould cavity 2 via entry port 3, for the purposes of forming an aerosol dome 4. For reasons of clarity only half of the mould cavity 2 has been shown whilst the full dome 4 is shown.

A shuttle carriage 5 adapted for horizontal linear movement along a slideway or track 6, supports a means for removably inserting a core pin 7 into the mould cavity 2. The means for removably inserting a core pin comprises a hydraulic actuator 8. Shuttle carriage 5 also supports a means for delivering a preformed plastic nozzle insert 9 to mould cavity 2. The means for delivering the preformed plastic nozzle insert comprises a hydraulic actuator 10, which is located adjacent to hydraulic actuator 8.

As shown in Figure 2, hydraulic actuator 8 is adapted to be actuated in direction Y to allow insertion of core pin 7 into mould cavity 2, which occurs prior to injecting the melt into mould cavity 2. The insertion of core pin 7 within mould cavity 2 allows for an aperture (or opening) 11 to be formed in the dome 4 during injection moulding thereof. Actuator 8 may then be retracted after the dome is moulded thereby removing core pin 7 from the mould cavity and aperture 11. As shown in Figure 3, shuttle carriage 5 may then be linearly moved in a direction shown by arrow X in the horizontal plane, to allow the actuator 8 to be moved away from the aperture 11. As shown in Figures 4 and 5, shuttle carriage 5 moves to a position where the longitudinal axis of actuator 10 aligns with aperture 11. Preformed nozzle insert 9, which is being carried by a support (not shown) on carriage 5 near the end 12 (see Figure 5) of actuator 10, is then able to be urged into aperture 11 by extending actuator 10. Removal of the core pin 7 and urging of the preformed nozzle insert 9 into aperture 11 of the newly formed dome 4 occurs whilst the dome is still in the mould cavity. The urging of preformed nozzle insert 9 into aperture 11 preferably occurs a short period of time after plastic dome 4 is initially formed, say within 10 seconds and preferably within about 3 to 10 seconds. The newly formed dome 4 must have cooled sufficiently enough to allow for nozzle insert 9 to be inserted into dome aperture 11. Shrinkage of the dome aperture 11 occurs thereafter as the dome 4 further cools and sets to ensure that nozzle insert 9 is integrated within the dome aperture 11. Thereafter, the mould cavity 2 may be opened. When a finished dome 4 with integrated nozzle insert 9 has been formed, the actuator 10 is retracted and shuttle carriage 5 moved in the opposite direction to arrow X, thereby aligning the actuator 8 with mould cavity 2, prior to recommencing the cycle of inserting core pin 7 into the mould cavity as shown in Figures 1 and 2. The finished dome 4 with integrated nozzle insert 9 can then be ejected from mould cavity 2 in a conventional manner utilising conventional ejection means.

The device 1 has a hopper 14 for storing a plurality of preformed nozzle inserts 9 therein which have been previously and separately formed. A delivery tube 15 is adapted to allow preformed nozzle inserts 9 to be delivered one at a time and supported at the end 12 of the actuator 10 when it is in the retracted position as shown in Figures 1 and 2. Hopper 14 and tube 15 are shown schematically without full detail in similar manner to the other components of the device. It should be understood that in an alternative not shown embodiment, the tube 15 may be replaced by some means of delivery such as a slide. Hopper 14 includes a feed mechanism which ensures that preformed nozzles 9 are fed into delivery tube 15 in a correct orientation for placement by the actuator 10 into the mould cavity 2.

A guideway/support mechanism ensures a preformed nozzle insert 9 remains in the correct orientation as it exits the delivery tube 15, engages end 12 of actuator 10 and is urged into mould cavity 2 for integration with the dome. For reasons of clarity, the guideway/support mechanism, which in combination forms a nozzle insert insertion assembly, has been omitted from the figures. Hopper feed mechanisms and guideway/support mechanisms are well-known to those skilled in the art of aerosol valve manufacture and assembly.

By employing the device and method of the above mentioned embodiment, it is possible to use the same mould cavity to manufacture aerosol domes having identical bodies but having different spray characteristics by varying the type of preformed nozzle insert being fed into the device. This provides an important cost advantage over the prior art.

Whilst a preformed nozzle may be made of a plastic similar to that of the remaining portion of the finished dome, it is possible to utilise a preformed nozzle insert made of a different plastic than that of the plastic used to form the remaining part of the finished dome. This is important in that the properties of certain plastics are better suited for certain nozzle configurations. As such it is possible to manufacture the remaining portion of the dome of a cheaper plastic than that which may be necessary for the nozzle insert. An example may be where the plastic used for the dome is polyolelfin and the plastic used for the nozzle insert is polyacetal.

It should be readily understood that the above referenced embodiment describes an injection moulding device comprising one mould cavity for ease of reference. However, in another not shown embodiment the device may comprise of plurality of mould cavities, each of which has one or more associated shuttle carriages, each carriage carrying means for removably inserting a core pin into the respective mould cavity, and a means for delivering a preformed plastic nozzle insert to the respective mould cavity. In such an embodiment the preformed nozzle inserts may be delivered from a centralised hopper, or alternatively delivered from a plurality of hoppers each of which is associated with one or more mould cavities.

It should also be readily understood that whilst the shuttle carriage 5 carrying actuators 8 and 10 in the above described embodiment travels in a linear horizontal plane, it may in other not shown embodiments travel in a different linear plane or alternatively travel rotationally. Furthermore, the hydraulic actuators of the above described embodiment may in other embodiments be replaced by other actuator means such as pneumatic or mechanical actuators.

It should be obvious to those skilled in the art that numerous variations and modifications could be made to the method and device without departing from the spirit and scope of the invention.

Claims

1. A method for manufacturing and injection moulded plastic dome for an aerosol valve and associated container comprising the steps of:

(i) inserting a removable core pin into a mould cavity adapted to form said dome, said core pin being shaped to form an aperture in the dome for receiving a nozzle insert;

(ii) injecting plastic melt into said mould cavity to form said dome;

(iii) removing said core pin from said mould cavity; and

(iv) inserting a separately-formed nozzle insert from outside the mould into said aperture within said dome whilst the dome remains in the mould cavity, whereby said nozzle insert is integrated with said injection moulded dome.

2. The method of claim 1 , and further including the step of effecting the insertion of the nozzle insert into the dome aperture shortly after the injection of the melt and upon the initial solidification of the dome, whereby said aperture shrinks about the nozzle insert upon cooling.

3. The method of claim 2, and further wherein the insertion of the nozzle insert is within ten (10) seconds after the injection of the melt.

4. The method of claim 3, and further wherein the insertion of the nozzle insert is within three to ten (3 - 10) seconds after the injection of the melt.

5. A device for injection moulding a plastic dome for an aerosol valve and associated container comprising:

at least one mould cavity for moulding said dome, and at least one means for injecting melt into said cavity; characterised in that said device further comprises at least one means for removably inserting a core pin into said mould cavity to allow for the formation of an aperture in the dome for receiving a nozzle insert, and at least one means for inserting, after said core pin is removed from the mould cavity, a preformed nozzle insert from outside the mould into said dome aperture while said dome is within the mould cavity, whereby said nozzle insert is integrated with the dome.

6. A device for injection moulding a plastic dome for an aerosol valve and container as claimed in claim 5, wherein the means for removably inserting said core pin comprises a first actuator means.

7. A device for injection moulding a plastic dome for an aerosol valve and container as claimed in claim 5, wherein the means for inserting the preformed nozzle insert comprises a second actuator means.

8. A device for injection moulding a plastic dome for an aerosol valve and container as claimed in claim 6, wherein the first actuator means is mounted on a shuttle carriage for movement relative to the mould cavity.

9. A device for injection moulding a plastic dome for an aerosol valve and container as claimed in claim 7, wherein the second actuator means is mounted on a shuttle carriage for movement relative to the mould cavity.

10. A device for injection moulding a plastic dome for an aerosol valve and container as claimed in claim 7, wherein the preformed nozzle is delivered to the second actuator means from a hopper delivery system adapted to hold a plurality of such preformed nozzles.