Packaging locking and indication system

A device for dispensing a material that has a limited period of utility, a novel device comprises a first part containing the material and a second part, wherein the first and second parts have mutual engagement means and can be disengaged to allow the material to be dispensed, wherein the device includes, located within the device, control mechanisms that can be activated to initiate a time-controlled period of use and that, at the end of that period, causes the first and second parts to be permanently engaged.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national stage application of International Application No. PCT/GB2009/050368, filed Apr. 15, 2009, which International application was published on Oct. 22, 2009, as International Publication No. WO2009/127867 A1 in the English language, which application is incorporated herein by reference. The International application claims priority of Great Britain Patent Application No. 0806907.2, filed Apr. 16, 2008, Great Britain Patent Application No. 0814057.6, filed Aug. 1, 2008, Great Britain Patent Application No. 0818367.5, filed Oct. 7, 2008, which applications are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the packaging of non-durable products such as cosmetics, skin care products, sun care products, toiletries, foodstuffs, beverages and certain pharmaceutical products and other non-durable products, principally in containers with reusable closures, the quality and efficaciousness of which deteriorate with respect to time and or exposure to excessive temperature, humidity, light and air and or to the presence of microbes from the point of manufacture or from the first occasion at which the package is opened by the end user.

BACKGROUND OF THE INVENTION

The quality and efficaciousness and in some instances safety of non-durable products deteriorate over time, requiring the packaging within which they are contained to display a “Use By”, “Best Before”, “Expiration” or other date to indicate when the product will become unsuitable for use. Many products deteriorate at an accelerated rate once the packaging within which they are contained has been opened, the causes of which can be physico-chemical degradation due to time, exposure to excessive temperature, humidity, light and air and or microbial contamination. When the deterioration of a product after its opening could cause harm to the consumer, for example the degradation of the U.V. protection of a sun care product or the potential for microbial contamination of a mascara product, the period of time that the product will remain safe to use after opening or “Period after Opening” is often displayed on the product package. However, consumers frequently overlook or disregard the “Use By” or “Period after Opening” information provided, or fail to remember when a product package was first opened, with sometimes deleterious effects to product quality, health and safety.

With increasing consumer demand for non-durable products with improved quality, safety and lower preservative content, several improvements to the packaging for non-durable products have been suggested. GB2387941 describes a closure for preventing the opening of a bottle after an expiry date and consists of a conventional cap with an internal thread which mates with a threaded sleeve situated within a recess about the neck of a bottle. The sleeve is prevented from rotating about the neck of the bottle by lugs, manufactured from a bio-degradable plastics material, formed on the sleeve and located within indents formed on the neck of the bottle so that the torque required to remove or secure the cap to the bottle is transferred to the lugs. Once the plastic has degraded to a sufficient extent, the force required to remove the cap causes the lugs to shear, thus enabling the sleeve to rotate with the cap about the neck of the bottle, thereby preventing its removal. However, due to the imprecise nature of predicting when the bio-degradable material will degrade sufficiently for the lugs to shear, especially when exposed to changing conditions of temperature and humidity, it is difficult to ensure that the removal of the cap will be prevented within an acceptable time tolerance, thereby rendering the device impracticable for use in most product applications.

FR2887646 describes a time-indicating unit incorporated into the packaging for a fluid product-dispensing device, to provide a visual indication of elapsed time, to reduce the risk to a consumer caused by using a device containing expired product. The time-indicating unit is automatically activated by means of a push button upon first use of the product, but suffers the disadvantage that the user is relied upon to correctly interpret and act in accordance with the indication provided.

A number of time-temperature indicators have become available. Timestrip®, produced by Timestrip Plc (UK), for example, is a label-type device which relies on the migration of a tinted liquid through a micro-porous material at a rate dependant on temperature to provide an indication of time elapsed and is designed to monitor the shelf life of a wide range of opened or un-opened products to provide the consumer with a visual indication of when a product has reached the end of its useful life but suffers the disadvantage that the user is relied upon not only to activate and attach the device to the product package but also to correctly interpret and act in accordance with the indication provided. Fresh-Check® produced by the Temptime Corporation (USA), and MonitorMark™, produced by the 3M Corporation (USA), are label type time-temperature indicating devices designed to be affixed to or placed within the packaging for non-durable products and rely, respectively, upon the gradual darkening of a chemical indicator and the migration, at a rate dependant upon time and temperature, of a coloured indicator along a wicking material to provide the end user with a visual indication of when a product has reached the end of its useful life but, once again, suffer the disadvantage that the user is relied upon to correctly interpret and act in accordance with the indication provided.

To ensure product quality and efficacy and to safeguard the health and safety of consumers, a need therefore exists to prevent the use of non-durable products once the useful life of the product has been exceeded.

SUMMARY OF THE INVENTION

As will become apparent from the following description, and as expressed in the claims, there are at least 3 aspects of the present invention. In one aspect, this invention prevents disengagement of a two-part device after a predetermined time, so that dispensing of a material from one of the parts is prevented. In a second aspect, in consequence of a mechanism beyond the user's control, the device provides a display at the end of that period, to warn the user. In a third aspect, by similar means, tampering with the device is evident.

According to the present invention, a time or time-and-storage-conditions-dependant locking system for a product package incorporates, as desired, an indicator to provide the user with feedback as to the state of the locking system and to provide evidence that the package has been opened, the indicator aspect of the invention, whether time or time and storage conditions dependant or provided solely to indicate that a package has been opened, being applicable to the design of a product package independently of the product package locking system, comprising a first part containing a material to be dispensed or utilised, the material having a predetermined acceptable period of utility subject, or not, to its conditions of storage and or usage, and a second part which engages the first part and can be disengaged or displaced to allow the material to be dispensed or utilised through an aperture in the first part, and characterised by a means within the device composed of a locking means acting in unison with a measurement means, whereby, when the predetermined period of utility has elapsed, the first and second part cannot be disengaged or displaced and incorporating as desired a visual indication of the state of the means within the device.

A particular advantage of the present invention is that rather than relying on the end user to correctly identify, remember and act in accordance with the “Use By” or “Period after Opening” information displayed on a product package, or interpret, act in accordance with and in some cases activate an indicating device that may be attached to a product package, the locking system of the invention physically prevents the product from being dispensed from or utilised within the package after a predetermined period, subject, or not, to the storage conditions of the package, has elapsed.

The present invention utilises control means which can be activated, to initiate a time-controlled period of use, and which prevents disengagement after that period. Initiation can be at any suitable time, e.g. on first opening, and is not under the user's control.

A further advantage of the invention is that, when used to prevent the use of a product once its period after opening has expired, the indicator of the device may be so arranged as to provide, upon the first opening of the package, an indication that the period after opening has commenced and thus, with particular significance to the display and storage of products in a retail setting, provides evidence that the package has been opened, or “tamper evidence”.

DESCRIPTION OF PREFERRED EMBODIMENTS

The first part of the invention may take any suitable form such as a container for a liquid or dry substance or other consumable product such as a water filter for example. Examples of materials that may be contained within the first part will be well known to those of ordinary skill in the art. They include cosmetics and colour cosmetics, e.g. mascara, eye pencils, eye liner, eye shadow, foundation, concealer, blusher, lip liner, lip gloss and lipstick, skin care products e.g. moisturising products, body oil, toners, make-up remover and depilatories, sun care products, e.g. sunscreen and self-tanning lotion, eye care products e.g. eye wash, eye drops and contact lens solution, pharmaceutical and medical products, e.g. vaccines, insulin, ear drops, ointments and cough and cold syrups and foodstuffs etc. The material may be in a single piece or discrete pieces. Depending on the nature of the material, means may be provided for its advancement through an aperture in the first part, whereby the user gains ready access to a further supply of the material or an applicator or other means may be provided to enable the material to be accessed and or applied or used by the user.

The second part of a device of the invention may take any suitable form such as a screw cap, hinged lid, valve or other reusable closure for a container. Preferably, the second part is provided with a means, such as a ratchet in the case of a screw cap or hinged lid, to enable the second part to be re-engaged or replaced should the first and second parts be disengaged or displaced when the predetermined period elapses.

The measurement means within the device may be of any nature suitable for the measurement of time or time and storage conditions, including temperature, humidity, light, air and or microbial contamination.

The measurement means within the device may be of an electrical-electronic nature such as a battery-operated electronic timer circuit so configured as to operate a shape-memory-alloy actuator, solenoid or other electrical-mechanical device at a predetermined time after the device has been activated, the electronic timer circuit including, or not, a monitoring capability for one or more storage conditions.

Alternatively, the measurement means within the device may be of a mechanical nature such as a spring-loaded piston and cylinder arrangement closed by a gas-permeable barrier, the spring so configured as to generate a positive pressure or partial vacuum within the cylinder, the gas pressure within the cylinder increasing or decreasing, depending on the configuration, with respect to the volume of gas transmitted by the gas-permeable barrier over time. The gas transmission rate of the gas-permeable barrier may be a function of its material or materials of construction, method of manufacture, thickness, area, temperature, humidity and the pressure differential across the barrier. Transmission results in either a relative movement of the piston with respect to the cylinder over time, or the displacement of the piston relative to the cylinder at a specific pressure differential, relative to temperature, humidity and external gas pressure. In an alternative spring-loaded piston and cylinder arrangement, the piston is not sealed to the bore of the cylinder and is so configured as to be capable of moving through a viscous fluid contained within the cylinder at a controlled rate, thereby resulting in a relative movement of the piston with respect to the cylinder over time, the viscosity of the fluid and hence the rate at which the piston is able to move through the viscous fluid being a function of temperature.

The locking means may be of any form suitable for preventing the disengagement or displacement of the first part relative to the second part, such as a movable element so configured as to prevent or enable, in concord with the state of the measurement means, the relative rotation of a first annular piece about a second annular piece, or a moveable element so configured as to prevent or enable, in concord with the state of the measurement means, the linear movement of a first piece with respect to a second piece.

Alternatively, the locking means may be so configured as to provide evidence that the package has been opened only.

The indicator of the device may be so arranged as to provide the user with feedback as to the state of the means before activation, upon activation and once the “use by” or “period after opening” has expired or may be so arranged as to provide, upon activation, a progressive indication of the time elapsed since activation or the time remaining before the “use by” or “period after opening” has expired.

Alternatively, the indicator of the device may be so arranged as to provide evidence that the package has been opened only, in concord with the suitable locking means.

Typically, a display of information in a device of the invention will be of different states, indicating one or more of: manufacture, packaging, initiation of the period of use, the period of utility, and the end of that period, i.e. that the device should no longer be used. For example, means within the second part may be provided, giving a display through a window or aperture in the outer wall of the second part.

Optionally, an audible or visual means acting in accordance with the state of the measurement means of the device may be included with or independently of the indicator of the device to signify to the user that the expiration of the “use by” or “period after opening” is approaching. Suitable audible means include a piezo sounder or other audible device acting in unison with the electronic timer and so configured as to play a recorded message or emit a tone or sequence of tones at regular intervals for a predetermined period before the “use by” or “period after opening” expires. Suitable visual means include a light-emitting diode or other light-emitting device acting in unison with the electronic timer and so configured as to flash at regular intervals for a predetermined period before the “use by” or “period after opening” expires.

Also optionally, an audible or visual means acting in accordance with the state of the measurement means of the device may be included with or independently of the indicator of the device to signify to the user, upon initiation, that the “period after opening” has begun. Suitable audible means include a piezo sounder or other audible device acting in unison with the electronic timer and so configured as to play a recorded message or emit a tone or sequence of tones. Suitable visual means include a light-emitting diode or other light-emitting device acting in unison with the electronic timer.

A first embodiment of the invention will now be described by way of example only with reference toFIGS. 1 to 8of the accompanying drawings, in which:

FIG. 1shows, in perspective, the constituent parts of a product package consisting of a container with a screw cap incorporating an electronic-timer-and-latch-type locking system with visual indicator.

FIG. 2shows, with the outer cap in section, the closed product container prior to the activation of the electronic-timer-and-latch-type locking system.

FIG. 3shows, with the outer cap in section, the open product container with the electronic-timer-and-latch-type locking system activated.

FIG. 4shows, with the outer cap in section, the container and screw cap locked together by means of the electronic-timer-and-latch-type locking system.

FIG. 5shows the closed product container incorporating an electronic-timer-and-latch-type locking system with indication apertures.

FIG. 6shows the indication displayed in the indication apertures prior to the activation of the electronic-timer-and-latch-type locking system.

FIG. 7shows the indication displayed in the indication apertures upon activation of the electronic-timer-and-latch-type locking system.

FIG. 8shows the indication displayed in the indication apertures with the container and screw cap locked together by means of the electronic-timer-and-latch-type locking system.

With reference toFIGS. 1 to 8, the product package incorporating an electronic-timer-and-latch-type locking system with visual indicator comprises a container1and a screw cap assembly2consisting of an outer cap3, with indication apertures4, locked together with, but free to rotate about, an inner cap5by means of a male rotatable annular snap fit6and a female rotatable annular snap fit7. The outer cap3is closed at one end by an end cap8, the positioning of which is determined by an index key9and index key slot10. The inner cap5forms a piston11at one end, over which is placed a spring12and an actuator13, the upper cylindrical outer face of which is printed with an indicator flag. Placed within the upper part of the actuator13is a timer/latch module14comprising a latch15, a shape-memory-alloy actuator wire16, a switch17, a battery18, and an electronic timer circuit with piezo sounder (not shown).

At assembly, the upper parts of the locking tabs19on the actuator13are held against the underside of the slotted shoulder20within the outer cap3by means of the spring12. Clockwise movement of the outer cap3relative to the actuator13is prevented by the rotation limiters21, enabling the screw cap assembly2to be screwed onto the container1without relative movement between the outer cap3and inner cap5, the actuator13being prevented from rotating relative to the inner cap5by actuator guides22and guide slots23as shown inFIGS. 1 and 2and the indication, as shown inFIG. 6, is provided in the indication apertures4, as shown inFIG. 5.

Upper friction stops24on the inner cap5and lower friction stops25on the container1are so proportioned as to ensure that the torsional force required to rotate the outer cap3about the inner cap5, with the spring12at its compressed length, is less than the torsional force required to unscrew the female thread (not shown) within the cap assembly2about the male thread26on the container1, as shown inFIGS. 1 to 5.

When the outer cap3is rotated anticlockwise by fifty degrees about the inner cap5, the slots in the slotted shoulder20line up with the locking tabs19on the actuator13, the rotation limiters21preventing any further anticlockwise rotation of the outer cap3relative to the actuator13and the actuator13, under the force of the spring12, is moved upwards relative to the inner cap5until the switch17is closed by the slotted shoulder20on the outer cap3(thereby activating the electronic timer circuit) and the upper surface of the latch15makes contact with the underside of the slotted shoulder20on the outer cap3preventing any further vertical movement of the actuator13relative to the outer cap3and providing the indication as shown inFIG. 7in the indication apertures4as shown inFIG. 5and hence indicating to the user that the package has been opened and that the period after opening has commenced.

As the locking tabs19are now situated in the slots of the slotted shoulder20, the actuator13, and hence the inner cap5cannot be rotated relative to the outer cap3, thereby enabling the screw cap assembly2to be disengaged and re-engaged with the container1in the manner of a common screw cap, as shown inFIGS. 1,3and5.

Once the period after opening has commenced in accordance with the above, the electronic timer circuit begins to count down from a pre-determined time period.

From a pre-specified point in the count down, the piezo sounder periodically emits an audible signal to warn the user that the period after opening will soon expire.

When the count reaches zero the electronic timer circuit connects power to the shape-memory-alloy actuator wire16causing it to contract thereby retracting the latch15. With the latch15retracted, the actuator13, under force of the spring12is free to move upwards relative to the outer cap3until the locking tabs19and slotted shoulder20disengage, the switch17is opened, and the actuator13and the end cap8make contact, as shown inFIGS. 1 and 4, thereby irreversibly providing the indication as shown inFIG. 8in the indication apertures4as shown inFIG. 5, and hence indicating to the user that the period after opening has elapsed.

Should the period after opening elapse whilst the screw cap assembly2and the container1are disengaged, lower ratchet teeth27on the actuator13and upper ratchet teeth28on the end cap8enable the screw cap assembly2to be screwed onto the container1, a small compression of the spring12providing for the ratchet action as shown inFIGS. 1,4and5.

Once the upper friction stops24and lower friction stops25have made contact and the screw cap assembly2cannot be further rotated clockwise relative to the container1, any attempt to unscrew the screw cap assembly2from the container1will result in the outer cap3rotating about the inner cap5without any displacement of the inner cap5relative to the container1hence preventing the contents of the container1from being used as shown inFIGS. 1,4and5.

A second embodiment of the invention will now be described by way of example only with reference toFIGS. 9 to 16of the accompanying drawings, in which:

FIG. 9shows, in perspective, the constituent parts of a product package consisting of a container with a screw cap incorporating a spring-loaded piston, cylinder and gas-permeable-barrier-type, time-temperature-dependant locking system with visual indicator.

FIG. 10shows, with the outer cap in section, the closed product container prior to the activation of the spring-loaded piston, cylinder and gas-permeable-barrier-type, time-temperature-dependant locking system.

FIG. 11shows, with the outer cap in section, the open product container with the spring-loaded piston, cylinder and gas-permeable-barrier-type, time-temperature-dependant locking system activated.

FIG. 12shows, with the outer cap in section, the container and screw cap locked together by means of the spring-loaded piston, cylinder and gas-permeable-barrier-type, time-temperature-dependant locking system.

FIG. 13shows the closed product container incorporating a spring-loaded piston, cylinder and gas-permeable-barrier-type, time-temperature-dependant locking system with indicator window.

FIG. 14shows the indication displayed in the indicator window prior to the activation of the spring-loaded piston, cylinder and gas-permeable-barrier-type, time-temperature-dependant locking system.

FIG. 15shows the indication displayed in the indicator window upon activation of the spring-loaded piston, cylinder and gas-permeable-barrier-type, time-temperature-dependant locking system.

FIG. 16shows the indication displayed in the indicator window with the container and screw cap locked together by means of the spring-loaded piston, cylinder and gas-permeable-barrier-type, time-temperature-dependant locking system.

With reference toFIGS. 9 to 16, the product package incorporating a spring-loaded piston, cylinder and gas-permeable-barrier-type, time-temperature-dependant locking system with visual indicator comprises a container29and a screw cap assembly30consisting of a transparent outer cap31, printed on its outer surfaces to provide an annular transparent indicator window32, locked together with, but free to rotate about, an inner cap33by means of a male rotatable annular snap fit34and a female rotatable annular snap fit35. The outer cap31is sealed at one end by a rotary seal36positioned within a rotary seal gland37on the inner cap33and at the other end by an end cap38, the positioning of which is determined by an index key39and index key slot40. The outer cap31, inner cap33, and end cap38are manufactured from a material with no, or a very low, permeability to air, thereby isolating the volume between the outer cap31, inner cap33and end cap38from fluctuations in atmospheric pressure and humidity. The inner cap33forms a piston41at one end, over which is placed a power spring42, a floating spring retainer43, a control spring44and an actuator45manufactured from a material with no, or a very low, permeability to air, the bore of the actuator45being sealed to the piston41by means of a piston seal46positioned within a piston seal gland47. Attached to the top of the actuator45in a gas tight manner is an indicator barrel48, the outer cylindrical face of which is printed with an indicator flag, with a seat49having an aperture at its centre, to which is adhered a gas-permeable barrier50so that any flow of air around the edges of the gas-permeable barrier50is prevented. Index pins51and index pin slots52ensure that the actuator45and indicator barrel48are correctly aligned and cannot rotate with respect to one another.

At assembly, the upper parts of locking tabs53on the actuator45are held against the underside of slotted shoulders54within the outer cap31by means of the power spring42and the control spring44. Clockwise movement of the outer cap31relative to the actuator45is prevented by rotation limiters55, enabling the screw cap assembly30to be screwed onto the container29without relative movement between the outer cap31and inner cap33. The actuator45is prevented from rotating relative to the inner cap33by actuator guides56and guide slots57as shown inFIGS. 9 and 10and no indication, as shown inFIG. 14is provided in the indication window32as shown inFIG. 13.

Upper friction stops58on the inner cap33and lower friction stops59on the container29are so proportioned as to ensure that the torsional force required to rotate the outer cap31about the inner cap33, with the power spring42and control spring44at their compressed lengths is less than the torsional force required to unscrew the female thread60on the cap assembly30about the male thread61on the container29as shown inFIGS. 9 to 12.

When the outer cap31is rotated anticlockwise by fifty degrees about the inner cap33, the slots in the slotted shoulder54line up with the locking tabs53on the actuator45, the rotation limiters55preventing any further anticlockwise rotation of the outer cap31relative to the actuator45and the actuator45, under the force of the power spring42, is moved upwards relative to the inner cap33until the floating spring retainer43makes contact with the underside of the slotted shoulders54on the outer cap31thus causing, as a result of the relative displacement of the actuator45with respect to the piston41, an increase in the pressure within the outer cap31and a pressure drop in the bore of the actuator45as shown inFIG. 11and providing the indication as shown inFIG. 15in the indication window32as shown inFIG. 13and hence indicating to the user that the package has been opened and that the period after opening has commenced.

As the locking tabs53are now situated in the slots of the slotted shoulder54, the actuator45, and hence the inner cap33cannot be rotated relative to the outer cap31, thereby enabling the screw cap assembly30to be disengaged and re-engaged with the container29in the manner of a common screw cap, as shown inFIGS. 9,11and13.

Once the period after opening has commenced in accordance with the above, air from the volume within the outer cap31is slowly transmitted to the bore of the actuator45, through the aperture in the indicator barrel48by means of the gas-permeable barrier50at a rate dependant upon temperature and the pressure differential between the bore of the actuator45and the volume within the outer cap31until such time as the force exerted by the control spring44between the floating spring retainer43and the actuator45is great enough to overcome the force exerted on the end of the actuator45due to the pressure differential between the bore of the actuator45and the volume within the outer cap31and the “break out” friction due to the piston seal46, at which point the control spring44pushes the actuator45upwards until the locking tabs53and slotted shoulder54disengage and the indicator barrel48and the end cap38make contact, enabling, as a result of this movement, the pressure in the bore of the actuator45and pressure in the volume within the outer cap31to equalise by means of the guide slots/pressure equalisation ports57as shown inFIG. 12and thereby irreversibly providing the indication as shown inFIG. 16in the indication window32as shown inFIGS. 9 and 13and hence indicating to the user that the period after opening has elapsed.

Should the period after opening elapse whilst the screw cap assembly30and the container29are disengaged, the lower ratchet teeth62on the indicator barrel48and the upper ratchet teeth63on the end cap38enable the screw cap assembly30to be screwed onto the container29, a small compression of the control spring44providing for the ratchet action, as shown inFIGS. 9,12and13.

Once the upper friction stops58and lower friction stops59have made contact and the screw cap assembly30cannot be further rotated clockwise relative to the container29, any attempt to unscrew the screw cap assembly30from the container29will result in the outer cap31rotating about the inner cap33without any displacement of the inner cap33relative to the container29, hence preventing the contents of the container29from being used, as shown inFIGS. 9,12and13.

A third embodiment of the invention will now be described by way of example only with reference toFIGS. 17 to 24of the accompanying drawings, in which:

FIG. 17shows, in perspective, the constituent parts of a product package consisting of a container with a screw cap incorporating a viscous fluid and non-sealed-piston-type, time-temperature-dependant locking system with visual indicator.

FIG. 18shows, with the outer cap in section, the closed product container prior to the activation of the viscous fluid and non-sealed-piston-type, time-temperature-dependant locking system.

FIG. 19shows, with the outer cap in section, the open product container with the viscous fluid and non-sealed-piston-type, time-temperature-dependant locking system activated.

FIG. 20shows, with the outer cap in section, the container and screw cap locked together by means of the viscous fluid and non-sealed-piston-type, time-temperature-dependant locking system.

FIG. 21shows the closed product container incorporating a viscous fluid and non-sealed-piston-type, time-temperature dependant locking system with indicator window.

FIG. 22shows a graduated indicator flag for a viscous fluid and non-sealed-piston-type, time-temperature-dependant locking system.

FIG. 23shows the indication displayed in the indicator window upon activation of the viscous fluid and non-sealed-piston-type, time-temperature-dependant locking system.

FIG. 24shows the indication displayed in the indicator window with the container and screw cap locked together by means of the viscous fluid and non-sealed-piston-type, time-temperature-dependant locking system.

With reference toFIGS. 17 to 22, the product package incorporating a viscous fluid and non-sealed-piston-type, time-temperature-dependant locking system with visual indicator comprises a container64and a screw cap assembly65consisting of a transparent outer cap66, printed on its outer surfaces to provide an annular transparent indicator window67, locked together with, but free to rotate about, an inner cap68by means of a male rotatable annular snap fit69and a female rotatable annular snap fit70. The outer cap66is closed at one end by an end cap71, the positioning of which is determined by an index key72and index key slot73.

The inner cap68forms at one end a cylinder74over which is placed a spring75and an actuator76with an aperture at its centre equal in diameter to the diameter of the cylinder74. Attached to the top of the actuator76is an indicator barrel77, with an aperture78at its centre, the outer cylindrical face of which is printed with a graduated indicator flag as shown inFIG. 22, index pins79and index pin slots80ensuring that the actuator76and indicator barrel77are correctly aligned and cannot rotate with respect to one another. Fixed to the mouth of the cylinder74is a cylinder cap81to prevent the escape of a viscous fluid (not shown) contained within the cylinder74. Placed within the cylinder74, and hence within the viscous fluid, and passing through an aperture in the cylinder cap81and the aperture78in the indicator barrel77, is a piston rod82with a piston bulb83at one end and a piston snap fit84at the other end. The piston rod82is proportioned so that when the piston bulb83is at its lowest point within the cylinder74, the shoulder of the piston snap fit84is positioned at a distance greater than the thickness of the slotted shoulder85within the outer cap66above the upper, inner surface of the indicator barrel77.

At assembly, the upper parts of the locking tabs86on the actuator76are held against the underside of the slotted shoulder85within the outer cap66by means of the spring75. Clockwise movement of the outer cap66relative to the actuator76is prevented by the rotation limiters87, enabling the screw cap assembly65to be screwed onto the container64without relative movement between the outer cap66and inner cap68, the actuator76being prevented from rotating relative to the inner cap68by actuator guides88and guide slots89as shown inFIGS. 17 and 18and no indication, as shown inFIG. 23, is provided in the indication window67, as shown inFIG. 21.

Upper friction stops90on the inner cap68and lower friction stops91on the container64are so proportioned as to ensure that the torsional force required to rotate the outer cap66about the inner cap68, with the spring75at its compressed length, is less than the torsional force required to unscrew the female thread92on the cap assembly65about the male thread93on the container64, as shown inFIGS. 17 to 21.

When the outer cap66is rotated anticlockwise by fifty degrees about the inner cap68, the slots in the slotted shoulder85line up with the locking tabs86on the actuator76, the rotation limiters87preventing any further anticlockwise rotation of the outer cap66relative to the actuator76, and the actuator76and hence the indicator barrel77, under the force of the spring75, is moved upwards relative to the inner cap68until the shoulder of the piston snap fit84on the piston rod82makes contact with upper, inner surface of the indicator barrel77thus providing, as a result of the relative displacement of the actuator76with respect to the inner cap68, the indication, as shown inFIG. 23in the indication window67as shown inFIG. 21, and hence indicating to the user that the package has been opened and that the period after opening has commenced.

As the locking tabs86are now situated in the slots of the slotted shoulder85, the actuator76, and hence the inner cap68cannot be rotated relative to the outer cap66, thereby enabling the screw cap assembly65to be disengaged and re-engaged with the container64in the manner of a common screw cap, as shown inFIGS. 17,19and21.

Once the period after opening has commenced in accordance with the above, the force exerted by the spring75, through the actuator76and indicator barrel77, on the shoulder of the piston snap fit84causes the piston bulb83to slowly move through the viscous fluid contained within the cylinder74at a rate dependant upon the viscosity of the fluid, the viscosity of the fluid being a function of temperature, until the locking tabs86and slotted shoulder85disengage and the indicator barrel77and the end cap71make contact, as shown inFIGS. 17 and 20, thereby irreversibly providing the indication as shown inFIG. 24in the indication window67as shown inFIG. 21, and hence indicating to the user that the period after opening has elapsed.

Should the period after opening elapse whilst the screw cap assembly65and the container64are disengaged, lower ratchet teeth94on the indicator barrel77and upper ratchet teeth95on the end cap71enable the screw cap assembly65to be screwed onto the container64, a small compression of the spring74providing for the ratchet action as shown inFIGS. 17,20and21.

Once the upper friction stops90and lower friction stops91have made contact and the screw cap assembly65cannot be further rotated clockwise relative to the container64, any attempt to unscrew the screw cap assembly65from the container64will result in the outer cap66rotating about the inner cap68without any displacement of the inner cap68relative to the container64hence preventing the contents of the container64from being used as shown inFIGS. 17,20and21.

A fourth embodiment of the invention will now be described by way of example only with reference toFIGS. 25 to 29of the accompanying drawings, in which:

FIG. 25shows in perspective, the constituent parts of a product package consisting of a container with a screw cap incorporating a tamper-evidence-only-type locking system.

FIG. 26shows with the outer cap in section, the closed product container prior to the activation of the tamper-evidence-only-type locking system.

FIG. 27shows, in perspective, the closed product container prior to the activation of the tamper-evidence-only-type locking system.

FIG. 28shows, with the outer cap in section, the open product container after activation of the tamper-evidence-only-type locking system.

FIG. 29shows in perspective, the open product container after activation of the tamper-evidence-only-type locking system.

With reference to the accompanying drawings, the package incorporating a tamper-evidence-only-type locking system comprises a container96and a screw cap assembly97consisting of an outer cap98locked together with, but free to rotate about, an inner cap99by means of a male rotatable annular snap fit100and female rotatable annular snap fit101and containing a spring102, and an actuator103with locking tabs104the outer faces of which are printed with an indicator flag105. The outer cap98is manufactured from a transparent material and printed on its outer surfaces to provide a transparent indicator window106, as shown inFIGS. 25 to 29.

At assembly, the upper parts of the locking tabs104on the actuator103are held against slotted shoulder107within the outer cap98by means of the spring102. Clockwise movement of the outer cap98relative to the actuator103is prevented by rotation limiters108, enabling the screw cap assembly97to be screwed onto the container96without relative movement between the outer cap98and inner cap99, actuator103and spring102, the actuator103being prevented from rotating relative to the inner cap99by actuator guides109and guide slots110, as shown inFIGS. 25,26and27.

Upper friction stops111on the inner cap99and lower friction stops112on the container96are so proportioned as to ensure that the torsional force required to rotate the outer cap98about the inner cap99is less than the torsional force required to unscrew the inner cap99about the male thread113on the container96, as shown inFIGS. 25 and 26.

When the outer cap98is rotated anticlockwise by fifty degrees about the inner cap99, the slots in the slotted shoulder107line up with the locking tabs104on the actuator103, the rotation limiters108preventing any further anticlockwise rotation of the outer cap98relative to the actuator103. The actuator103, under the force of the spring102, is then moved into contact with the upper part of the outer cap98thus irreversibly locking the outer cap98to the inner cap99and enabling the indicator flags105to be viewed through the indicator windows106and providing a permanent indication to the user that the package has been opened. The screw cap assembly97may now be disengaged and re-engaged with the container96in the manner of a common screw cap, as shown inFIGS. 25,28and29.

The retraction of the latch may be achieved by the contraction of a shape-memory-alloy actuator wire as shown in the first embodiment of the invention or by any other suitable thermal shape-memory-alloy effects.

The seal between the cylinder of the actuator and the piston of the inner cap may be achieved by means of an ‘O’ ring as shown in the second embodiment of the invention or by any other suitable means such as a ‘U’ seal, ‘X’ seal, or a composite seal comprising, for example, a polymer jacket energised by a metallic spring, a polymer jacket energised by an ‘O’ ring or a polymer jacket energised by a spring element or elements formed on the end of the piston, by means of a single or multiple shot injection-moulding process, as an integral part of the inner cap.