SPECIFICATIONSealant packageThis invention relates to dispensing packages and is concerned particularly but not exclusively with packages for viscous sealant compositions.
Various constructions of packages are known from which sealant compositions may be dispensed. For example one known package from which sealant composition may be dispensed comprises a stiff cylindrical plastics cartridge in which the composition is contained, which cartridge comprises an exit port through which the composition may be dispensed to a nozzle mounted thereon, a piston for closure of an open end of the cartridge and a separate plunger for exerting pressure on the piston to extrude composition through the exit port. The plunger of this known arrangement is mounted, prior to its use as a plunger, on a clip on the cartridge, and in this "storage" condition extends alongside the cartridge.This known package is charged with sealant composition and is conveniently marketed in "blister packs" in which the cartridge and plunger are mounted on a cardboard backer and enclosed thereon by a transparent protective blister of semi-rigid plastics material. It will be apparent that in this form of packaging the shape of and volume enclosed by the blister and thus the quantity of plastics material used for it, and the size and shape of the backer is determined largely by reference to the shape and volume of the object to be packaged.
When packages of sea lant are used to dispense sealant compositions it is common for sealant to drool until pressure within the cartridge is relieved, and this often results in an sightly and inconvenient sprue which may or may not harden, this causing greater or lesser problems in storage or when the cartridge next comes to be used.
Among objects of the present invention are to provide an improved form of package suitable for use inter alia with sealant compositions, which is simple to use and which results in cost savings in production of the package itself and or the blister package in which it is marketed.
We have now found that an improved package may comprise a cartridge and plunger of moulded plastics material of which the plunger is adapted for use both as a plunger to exert pressure on a piston housed in the cartridge in order dispense composition from the cartridge and as a shroud to be fitted over the cartridge when the cartridge is stored.
The invention provides in one of its aspects a package comprising a stiff plastics cartridge with an exit port and piston received within the cartridge in sealing engagement with an interior wall thereof for movement axially of the cartridge by means of a plunger to expel material from the cartridge through the exit port, a plunger comprising a stiffly resilient skirt portion and a cap portion, which plunger is adapted to be received within the cartridge and to be pressed onto the piston and which plunger is also adapted to be fitted over the nozzle so that the skirt portion extends around a major portion of the cartridge whereby the plunger may be held on the cartridge when the cartridge is in storage.
In a package according to the invention, the plunger is so constructed and arranged that it has sufficient compressibility for insertion in the cartridge, sufficient rigidity to permit its use as a plunger for exerting adequate pressure on the piston to expel composition from the cartridge and sufficient flexibility to permit expansion of at least a substantial portion thereof so that it may be clipped over the cartridge and so shroud the exit port of the cartridge.
In a preferred embodiment of the invention a sealing element is located on the cap portion so as to be disposed towards the exit port when the plunger is fitted over the cartridge.
In a preferred embodiment of the invention the cartridge is provided with an integrally formed nozzle, which may be punctured to provide the exit port, however, it is within the ambit of the invention to employ a detachable nozzle secured to the cartridge by any suitable means for example a screw thread, with the nozzle so arranged that composition expelled from an exit port of the cartridge may pass to the nozzle. The nozzle may be punctured in the same way as the integral nozzle. The nozzle may be punctured by slicing across the nozzle at a position and angle selected to provide an exit orifice of desired size commensurate with the desired geometrical character of a bead of composition to be extruded from the cartridge.Preferably the nozzle is punctured by means of a cut perpendicular to the central axis of the nozzle such that a minor portion of the nozzle is removed and such that the sealing element located on the cap portion of the plunger may be placed in sealing registration with the exit port of the nozzle.
In a preferred embodiment of the invention the cartridge and plunger have interior and exterior surfaces which are at least substantially cylindrical.
In a preferred embodiment of the invention an open end portion of the cartridge is flared to facilitate entry of the plunger.
In a preferred embodiment of the invention a skirt portion of the plunger comprises one or more slit extending lengthwise of the plunger so that it may be compressed slightly radially for insertion into the cartridge, or expanded slightly for clipping on the cartridge.
The invention also provides a blister display package comprising a package according to the last preceding paragraph enclosed on a backer by means of a preformed blister of transparent plastics material.
Among advantagea that a package according to this invention offers are a reduction in the quantity of material necessary to provide the blister display packaging and also a reduction in the production costs of providing a cartridge with an integral nozzle.
The shroud additionally serves to protect the nozzle and partially controls the sprue drooling from the nozzle after use or renders it less obtrusive.
Although a package according to this invention is primarily intended to be used to dispense sealants, it is not intended to limit the scope of the invention to this aspect only and it is envisaged that such packages may contain other pasty or fluid materials such as toothpaste or shoe cream.
In order that the invention may become more clear there now follows a detaiied description to be read with the accompanying drawings of one example package provided by the invention and illustrative thereof. It isto be understood that the illustrative package has been selected for description to illustrate the invention by way of example only.
In the drawings:Figure 1 is a side view of the illustrative package shown in storage,Figure 2 is a side view, partly in section, of the illustrative package shown ready for use.
The illustrative package comprises a cartridge (2) and plunger (12), which plunger is adapted for use both to exert pressure on a piston (see Figure 2) in order to dispense material from the cartridge and also to be used as a shroud over the cartridge when the cartridge is in storage (see Figure 1).
The cartridge (2) is a stiff cylindrical plastic cartridge of substantially uniform wall thickness and having an integral nozzle (4), the nozzle being intended to be punctured to provide an exit port (5).
The cartridge (2) contains a sealant (6) and is closed by a piston (8) in sealing engagement with an interior wall of the cartridge (2) which piston is moveable axially of the cartridge. An open end portion (10) of the cartridge is flared to facilitate entry of a plunger (12). The plunger (12) comprises a stiffly resilient skirt portion (14) of a plastics material which has interior and exterior surfaces which are at least partially cylindrical, and a cap portion (16).
Figure 1 shows the cartridge in storage with the plunger (12) mounted as a shroud over the c,artridge.
The skirt portion (14) extends around a major portion of the cartridge and is a resiliently clip fit thereon.
The skirt portion (14) is provided with a fairly wide slot (18) cut lengthwise of the skirt and two lengthwise slits (20) to allow sufficient flexibility for it to be mounted over the cartridge and also to be received within the cartridge. The cap portion (16) has a protuberance (22) located to register with the exit port of the nozzle (4). When required for use as a plunger, the plunger (12) is removed from the cartridge compressed slightly radially thereof and inserted into the open end (10) of the cartridge to press against peripheral portions of the piston (8). In order to expel sealant (6) from the cartridge, the nozzle (4) is punctured for example by cutting off an end portion to provide an exit port (5), and pressure is exerted on the piston (8) to move it axially in the direction of the exit port by means of the plunger (12) and thereby dispense the material. When no longer required as a plunger, it may be removed from inside the cartridge (2) and clipped on the outside with the protuberance (22) substantially in register with the exit port (15) of the nozzle to form a seal against ingress of moisture to the cartridge. The package comprising the cartridge and the plunger, the plunger (12) being mounted as a shroud over the cartridge (2), may be enclosed in a blister display package, the blister display package comprising the package (2) enclosed on a backer by means of a preformed blister of transparent plastics material.