FIELD OF THE INVENTION

This invention relates to a barrier system or shelf guard for shelving. BACKGROUND Much attention has been given to earthquakes in light of the recent Christchurch Earthquakes (Sep 2010, Feb 2011, Dec 2011). The loss of life and substantial damage to structures and goods seen as a result of these earthquakes, reinforces the importance of adequate preparation and protection. While much research and development is being done in the area of earthquake sensors, response systems and structural supports, there is a lack of development in the area of goods protection for shelving, especially for small to medium size retail firms that often do not have the monetary resources to properly equip their stores with expensive earthquake damage prevention systems.

It is a common problem that, during an earthquake, goods fall from shelves and suffer damage. Often, the damage may be irreparable and costly.

United States patent numbers 5,570,914 and 6,866,312 both disclose systems for goods protection in earthquakes, but these systems are aimed at household use and are focussed on latch mechanisms for preventing cupboard doors from opening during earthquakes.

United States patent number 7,234,254 provides a protection system for wine bottles in cellars and storage racks. In this system, wine bottles are laid horizontally in cradles within a rack. A ring is positioned around the neck of each bottle. The ring is tethered to the rack so that a bottle cannot be removed from the cradle unless the ring is removed from around the neck of the bottle. However, many retailers stand bottles, such as wine bottles, vertically on shelves and not in cradles so that customers can easily see the labels of the bottles and can make their selection. The system of US 7,234,254 is not well suited to prevent vertically standing bottles from falling off shelves during earthquakes. United States patent number 5,601, 198 discloses a system for preventing items from falling from shelves. This system comprises a flexible net projecting above and extending along the shelf to prevent items on the shelves from falling off. However, the net covers a significant portion of the area above the shelf at all times. This makes it difficult for items to be placed onto and removed from the shelf. In a retail situation, this system also has the drawback that it makes it difficult to see what goods are stocked on the shelves.

Therefore, there remains a need to provide a cost effective goods protection system that can be used to help prevent goods or items falling from shelves during an earthquake, especially in a retail situation or in any situation where the goods or items are to be clearly visible at all other times and/or where the goods or items are regularly placed onto or removed from the shelves. It is an object of at least preferred embodiments of the present invention to go at least some way toward overcoming the drawbacks of the prior art by providing a guard for shelving to help prevent items from falling from the shelving during an earthquake, tremor, or vibration of a predetermined magnitude, and/or to at least provide the public with a useful alternative. In this specification, where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents or such sources of information is not to be construed as an admission that such documents or such sources of information, in any jurisdiction, are prior art or form part of the common general knowledge in the art.

SUMMARY OF THE INVENTION

According to one aspect, the invention comprises a shelf guard comprising : an actuator comprising a vibration sensor and a lock; and a framework comprising an attachment member being attachable to a shelf and a barrier member being operably connected to and being adapted to move away from the attachment member, wherein the actuator is adapted to lock the guard in an inactivated position in which the guard is retracted and, upon sensing a vibration of a predetermined magnitude, is able to unlock the guard so that the barrier member can move away from the attachment member to form an activated position in which the guard is extended.

Preferably, the attachment member is an elongate member having first and second ends and the barrier member is an elongate bar having first and second ends.

Preferably, the framework further comprises a first scissor arm and a second scissor arm, each scissor arm having first and second ends, wherein the first scissor arm is pivotally connected to the first end of the attachment member at a first pivot point and is also pivotally connected to the second end of the barrier bar at a second pivot point, and wherein the second scissor arm is pivotally connected to the second end of the attachment member at a third pivot point and is also pivotally connected to the first end of the barrier bar at a fourth pivot point and wherein the scissor arms are pivotally connected to each other at a central pivot point.

At least one pivot point on the attachment member may comprise a sliding pivot for pivotally attaching the attachment member to the first or second scissor arm and at least one pivot point on the barrier bar comprises a sliding pivot for pivotally attaching the barrier member to the other scissor arm. In this form, the sliding pivots may each comprise a barrier height adjustment slot that extends along a portion of the respective attachment bar or barrier bar at or near an end of the attachment bar or barrier bar, as the case may be, and also comprise a pivot shaft that connects the attachment bar or barrier bar, as the case may be, to a respective scissor arm. Preferably, the first, second, third and fourth pivot points each comprise sliding pivots. More preferably, the sliding pivot includes an adjustable stop to adjust the effective length of the barrier height adjustment slot. In a preferred embodiment, each scissor arm comprises a clearance slot located in an inwardly facing edge of the scissor arm near one end of each scissor arm.

Preferably, at least a portion of the framework is covered by a cushioning material.

In a preferred embodiment, the attachment member is attached to or integral with a housing having a substantially U-shaped longitudinal cross-section to attach the guard to a shelf via at least one attachment point, and to house at least a portion of the framework of the guard when the guard is in the inactivated position.

Preferably, the actuator lock is retractable, the lock being adapted to project from the actuator to engage with the shelf guard to hold the shelf guard in the inactivated position, and to retract and disengage from the shelf guard to cause the shelf guard to move to the activated position.

In one form, the shelf guard comprises a passive actuator comprising an actuator mount, a biasing means in the form of a shaft and a spring, and a projecting lock in the form of a ball; wherein one end of the shaft is attached to the actuator mount and the spring is coiled around the shaft, the spring having a free end extending slightly beyond the free end of the shaft; and wherein the ball is positioned between the spring and the barrier member of the shelf guard, such that the spring presses the ball against the barrier member to hold the shelf guard in the inactivated position until a vibration of sufficient force causes the ball to fall from the spring and thereby release the barrier member.

In another form, the actuator of the shelf guard comprises: a ball within a housing having a concave floor; a pivot lever having an engagement latch; and a spring-loaded lock biased to a retracted position, wherein the engagement latch is adapted to engage with the lock to hold the lock in a projecting position in which the lock engages with the shelf guard to hold the shelf guard in the inactivated position and, upon movement of the ball within the housing, the ball contacts the pivot lever and causes the pivot lever to pivot and disengage the engagement latch from the spring-loaded lock, causing the lock to disengage from the shelf guard.

Preferably, the actuator of the shelf guard further comprises a sensor for sensing vibration, wherein the actuator is adapted so that the lock disengages from the shelf guard when the sensor senses a vibration of a predetermined magnitude.

Alternatively, the actuator may comprise a pull solenoid, the lock and pull solenoid being operably connected to each other and adapted so that the lock engages with the guard to hold the guard in the inactivated position and, upon receiving a signal from the sensor, the pull solenoid causes the lock to retract and disengage from the shelf guard.

In another alternative embodiment, the actuator comprises an electromagnet lock that engages with the shelf guard using magnetic force to hold the guard in the inactivated position and, upon receiving a signal from the sensor, an electrical circuit connected to the electromagnet is broken or the polarity of the electromagnet is reversed, to remove the magnetic attraction between the electromagnet and the shelf guard to cause the lock to disengage from the shelf guard. Preferably, in the inactivated position, the lock is adapted to engage with the barrier bar.

The locking mechanism of the actuator (for example, the projecting lock and the mechanical or electrical components that cause the lock to disengage the shelf guard when activated) may be attached to an actuator mount 45 for mounting the actuator to the shelf guard or to a shelf, as shown in Figure 12. The sensor may be operably connected to the actuator mount or it may be remote from the mount.

Preferably, a flexible material extends between the attachment member and the barrier member. One end of the flexible material may be attached to the attachment member and an opposing end of the flexible material may be attached to the barrier member, the flexible material being arranged such that it is folded or rolled when the shelf guard is in the inactivated position and unfurls or unrolls when the shelf guard moves to the activated position. The flexible material may be netting, mesh, or fabric.

Optionally, the actuator may comprise a drive system to drive the guard from an inactivated position to an activated position. The actuator may optionally be connected to an alarm to activate the alarm when the sensor senses a vibration of a predetermined magnitude.

Preferably, the attachment member comprises at least one attachment point to attach the shelf guard to a shelf.

Preferably, the shelf guard further comprises a drive system to cause the barrier member to move away from the attachment member, when the shelf guard moves from the inactivated position to the activated position.

In a second aspect of the invention, there is provided a combination of a shelf together with the shelf guard of the first aspect of the invention.

In accordance with another aspect of the invention, there is provided a guard for shelving, the guard comprising : a barrier attachable to shelving, the barrier being movable between an inactivated position in which an item in a storage area of the shelving is accessible, and an activated position in which the item in the storage area of the shelving is substantially inhibited from falling or being removed from the shelving; and a trigger for activating the barrier to move from the inactivated position to the activated position. The trigger is configured to activate the barrier when an earthquake, tremor, or vibration of a predetermined magnitude is detected.

In one embodiment, the guard is attachable underneath a shelf and the barrier falls or extends from the inactivated position to the activated position. In a preferred embodiment, the guard is placed on the front underside of each shelf. In an alternative embodiment, the barrier may be attached above the shelf and rise from the inactivated position to the activated position. In yet another embodiment, the guard may be attached to the front edge of a shelf and the barrier may extend upwardly or downwardly from that edge from an inactivated position to an activated position, or the barrier could fall downwardly from the inactivated position to the activated position.

In one embodiment, when the guard is in the activated position and attached to a shelf, the barrier will cover a portion of the vertical space between that shelf and the adjacent shelf above or below the shelf to which the guard is attached. Preferably, the barrier will cover a majority portion of the vertical space. The barrier may, in one form, cover the entire vertical space.

In one embodiment, the barrier comprises a framework. The framework preferably comprises a scissor mechanism having a plurality of bars. The bars preferably comprise a barrier bar, an upper bar, a first scissor bar, and a second scissor bar.

The bars may have a substantially regular cross-section. Alternatively, the bars may have reinforcing in the form of ribs or flanges.

In alternative embodiments; the framework may comprise other suitable arrangements of arms. The arms may be pivotably, and/or slidably connected to allow movement from the inactivated position to the activated position. Other alternative frameworks include telescopic arms, flexible arms, or resilient arms.

The first scissor bar is pivotally connected to the upper bar at a first end of the upper bar and is pivotally and slidably connected to the barrier bar at a second end. The second scissor bar is pivotally connected to the upper bar at a first end and is pivotally and slidably connected to the barrier bar at a second end. This arrangement of arms, pivots, and sliding pivots allows free vertical movement of the barrier bar while maintaining a horizontal level.

In alternative embodiments, the barrier may comprise a flexible material, such as net, mesh, or fabric, for example, that is able to move between an inactivated position and an activated position. In these alternative embodiments, the barrier may also include a framework as described above. Alternatively, the barrier may comprise a flexible material, such as net, mesh, or fabric, for example, without the framework. In the inactivated position, the flexible material may be folded or rolled and may unfold or unfurl from the inactivated position to the activated position.

In one embodiment, the trigger may be a passive trigger. In this embodiment, a sensor is combined with the trigger into one friction controlled unit in the form of a latch. The latch preferably has a spring-loaded ball in which the spring urges the ball against the barrier bar and holds the barrier bar in the inactive position under normal conditions. When vibrations or lateral movement reach a certain level, the friction between the ball and the barrier bar is overcome and the barrier bar drops to the activated position. The force applied by the spring is preferably adjustable. In another embodiment, the trigger may be a mechanical trigger.

In another embodiment, the trigger may be an electronic trigger. This embodiment preferably uses an earthquake or movement sensor. The sensor is preferably installed onto a load bearing wall in a central location of the store or premises in which the shelved goods are to be protected. In this embodiment, each shelving bay to be protected may be fitted with a signal receiver and a power supply. Each shelf is preferably fitted with a pull solenoid that pulls a latch, which in turn releases each barrier bar. A signal transmitter may be located locally to the barrier or remotely from the barrier. In addition, there may be one transmitter that sends signals to a plurality of guards or each guard may have its own transmitter. In the preferred embodiment, one transmitter is used to control every guard at a store or premises.

In an embodiment, the guard is fastened to the shelf. The guard may be fastened by bolts, screws, rivets, magnets, adhesive, or by any other suitable form of fastening the guard to the shelf. The guard may be retrofitted to an existing shelf or shelving. Alternatively, a shelf or set of shelving may be manufactured with the guard as part of the manufacturing process.

The terms "trigger" and "actuator" mean any part, device, system, or mechanism that, upon operation, causes the guard to move from an inactivated position to an activated position. The terms "trigger" and "actuator" are used interchangeably throughout this specification and claims. The term "extend" means for the guard to move from the inactivated position to the activated position whether by gravity or by drive means.

The term 'comprising' as used in this specification and claims, means 'consisting at least in part of. When interpreting statements in this specification that include the term 'comprising', other features besides the features prefaced by this term in each statement can also be present. Related terms such as 'comprise' and 'comprised' are to be interpreted in a similar manner.

It is intended that a reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates a reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

As used herein the term "(s)" following a noun means the plural and/or singular form of that noun.

As used herein the term "and/or" means "and" or "or", or where the context allows, "both". The invention consists in the foregoing and also envisages constructions of which the following gives examples only. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of example only and with reference to the accompanying drawings in which :

Figure 1 is a perspective view of a preferred form of guard attached to a shelf and in an inactivated position;

Figure la is an end view of the guard of Figure 1 attached to a shelf and in the inactivated position;

Figure lb is a front view of the front lip or edge of a shelf with the guard attached in an inactivated position and not visible behind the front lip of the shelf.

Figure lc is a bottom view of the guard of Figure 1 in the inactivated position and not attached to a shelf;

Figure Id is an enlarged end view of the guard attached to the inside front lip of a shelf, as shown in Figure la;

Figure 2 is a perspective view of the guard of Figure 1 attached to a shelf and in a semi-activated position, between the inactivated position and the activated position; Figure 2a is an end view of the guard of Figure 2 attached to a shelf and in the semi-activated position;

Figure 2b is a front view of the guard of Figure 2 in the semi-activated position and not attached to a shelf;

Figure 3 is a perspective view of the guard of Figure 1 attached to a shelf and in the activated position ;

Figure 3a is an end view of the guard of Figure 3 in the activated position;

Figure 3b is a front view of the guard of Figure 3 attached to a shelf and in the activated position;

Figure 3c is a rear view of the guard of Figure 3 not attached to a shelf and in the activated position; Figure 3d is an enlarged view of a sliding pivot of the guard of Figure 3;

Figure 4 is a partially cut away and exploded view of a sliding pivot shaft and pivot slot according to one aspect of the invention;

Figure 5 is a front view of a barrier height adjustment sliding pivot slot and pivot shaft according to another aspect of the invention; Figure 6 is a cross-sectional view of a pivot shaft according to one aspect of the invention. Figure 7 shows both an exploded view of the pivot shaft of Figure 6 and a perspective view of that pivot shaft;

Figure 8 is a perspective view of a shelving unit to which is attached a sensor and a plurality of guards according to one form of the invention and in which the guards are in the inactivated position and not visible on one side of the shelving unit and in the activated position on the other side of the unit;

Figure 8a is a perspective view of a guard according to one form of the invention, the guard being attached to shelving and in the activated position;

Figure 9 is a side view of one form of passive actuator according to one aspect of the invention; Figure 10 is a side view of one form of an electronically activated actuator according to one aspect of the invention;

Figure 11 is a side view of one form of a mechanically activated actuator according to one aspect of the invention;

Figure 12 is a schematic view of a latch/locking mechanism according to one aspect of the invention;

Figure 13 is an exploded view of one form of passive actuator according to the invention;

Figure 14 is a cross-sectional view of the actuator of Figure 13 where the lock is in the locked position.

Figures 15 and 16 are end views of different embodiments of lock for the actuator of Figure 14, both locks being in the locking position;

Figure 17 is a partial cross-sectional view of the actuator of Figures 13 and 14;

Figure 18 is a perspective view of a latch to be used with the lock of Figures 13 to 17; and

Figure 19 is a schematic view of an alternative embodiment of shelf guard according to the invention. Preferred embodiments of the invention will now be described by way of example only. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The barrier system or shelf guard of the present invention is designed to be attached to a shelf and to either extend substantially perpendicularly above the level of the shelf, to at least partially surround the shelf and help inhibit goods from falling from the shelf, or to extend substantially perpendicularly below the shelf, to at least partially surround the shelf immediately below and help inhibit goods from falling from that shelf. The shelf to be at least partially surrounded by the guard is referred to herein as the "target shelf". Either at least one guard may be used and positioned along the front of a shelf to help inhibit goods from falling from the front of the target shelf, or multiple guards could be positioned along the front and/or side(s) of a shelf to help inhibit goods from falling from the front and/or side(s) of the target shelf.

The guard may be adapted so that it can optionally be fitted underneath a shelf, preferably behind a downwardly projecting front lip of a shelf. In this form, when the guard is in its inactivated position, the guard is retracted and does not inhibit goods from being placed on or removed from the shelf to which the guard is attached. Nor does the guard inhibit goods from being placed on or removed from the target shelf immediately below. Furthermore, because the guard is retracted in its inactivated position, it does not restrict a person's ability to see the goods on the two shelves. The guard of the present invention comprises an actuator and a framework, in which the actuator comprises a retractable lock and may optionally comprise a sensor, and in which the framework comprises at least one attachment member and at least one barrier member. The attachment member comprises at least one attachment point at which to attach the guard to a shelf. When the guard is in the activated position, the barrier member moves away from the attachment member and substantially defines the height of the guard in the activated position.

Figures 1 to 3c show a preferred embodiment of the shelf guard 1 according to the invention. The guard is attachable underneath a first shelf 100 at one or more attachment points 40 and is adapted to form a barrier 30 along at least one edge of a second target shelf (positioned immediately below the first shelf) to help prevent goods from falling from the target shelf during an earthquake or tremor, as shown in Figures 8 and 8a. The barrier comprises the portion of the guard that extends from the attachment member when the guard is in the activated position. When this embodiment is attached beneath the front edge of a first shelf in the activated position, the guard extends substantially perpendicularly downward so that the barrier covers at least a portion of the area between the first shelf and target shelf to help inhibit goods from falling off the front edge of the target shelf. Thus, in the activated position, the barrier at least partially surrounds the target shelf.

The actuator/trigger 12 is adapted to cause the guard to move from an inactivated position, in which the guard is retracted (as shown in Figures 1 - Id), to an activated position, in which the guard is fully extended (as shown in Figures 3-3d), when a vibration of a predetermined magnitude occurs. The barrier of the guard may either extend downward by falling downward under the force of gravity or by being driven downward by a drive system.

In one embodiment, as shown in Figures 1 to 3d, the framework of the guard 1 comprises a scissor mechanism having a plurality of parts. In particular, the parts comprise: a barrier member in the form of a barrier bar 5; an attachment member in the form of an upper bar 2, providing at least one attachment point 40 by which to attach the framework to a shelf; a first scissor arm 3; and a second scissor arm 4. In the embodiment illustrated, the first and second scissor arms are in the form of scissor bars. Each of the bars of the scissor mechanism has substantially opposing first and second ends. The framework is arranged so that the upper bar 2 and barrier bar 5 are separated from each other by the scissor arms 3, 4. The scissor arms 3, 4 connect to each other at a central pivot point 10, although it is envisaged that the pivot point need not be located at the centre of each scissor arm. The ends of the scissor arms also connect to the ends of the upper bar and barrier bar, forming a crossbar or scissor arrangement between the upper bar and barrier bar.

In the scissor mechanism the bars of the framework are joined together with a pivot at each join. In a preferred embodiment, illustrated in Figures 3, 3b, 3c, and 3d, the pivot connections comprise three non-sliding or fixed pivot points and two sliding pivot points, which operate together so that the height of the barrier can be adjusted and set.

The first of the three non-sliding or fixed pivot points is located at an upper bar pivot 6 on the upper bar 2, at or near the second end 2b of the upper bar. At this upper bar pivot point, the second end of the upper bar 2b is connected to the first end 4a of the second scissor bar 4. The second non-sliding or fixed pivot point is located at a barrier bar pivot 7 on the barrier bar 5, at or near the second end 5b of the barrier bar. At the barrier bar pivot point, the second end 5b of the barrier bar is connected to the second end 3b of the first scissor bar 3. The third non-sliding or fixed pivot point is a central pivot 10 located at the intersection between the first and second scissor bars 3, 4. This intersection is typically, but not essentially, located at the centre of each of the two scissor bars. As will be appreciated by a person skilled in the art, the central pivot point may alternatively be located closer to the first ends of each scissor bar than to the second ends and vice versa. Furthermore, the distance between the first end of each scissor bar and the central pivot point may be different for each scissor bar.

As mentioned above, the upper bar fixed pivot 6 is adjacent (at or near) the second end 2b of the upper bar and the barrier bar fixed pivot 7 is adjacent (at or near) the corresponding second end 5b of the barrier bar. The fixed pivots each comprise a pivot shaft 20 held within an aperture in the respective bars. The diameter of each aperture for housing a pivot shaft is slightly larger than the diameter of the respective pivot shaft to enable the pivot shaft to rotate about its own longitudinal axis within the aperture. The shelf guard 1 has first and second ends. In this embodiment, the first end of the shelf guard corresponds to the first ends of the upper bar and barrier bar and the second end of the shelf guard corresponds to the second ends of the upper bar and barrier bar. Thus, in this embodiment, both the upper bar fixed pivot and barrier bar fixed pivot are located at a first end of the shelf guard. The fourth pivot point is an upper bar sliding pivot 8 located at a connection between the upper bar 2 and first scissor bar 3. The upper bar sliding pivot 8 is located adjacent (at or near) the first end 2a of the upper bar 2. The first sliding pivot 8 comprises a first barrier height adjustment slot 17a extending along part of the length of the upper bar 2, at or near the first end 2a of the upper bar. The sliding pivot 8 also comprises a pivot shaft 20 that projects through an aperture in the first end 3a of the first scissor bar 3, the barrier height adjustment slot 17a, and through an aperture in the first end 2a of the upper bar, to connect the first scissor bar 3 to the upper bar 2 in a sliding arrangement in which the pivot shaft 20 can move along the slot 17a and can rotate about its longitudinal axis within the slot. The fifth pivot point is a barrier bar sliding pivot 9 located at a connection between the barrier bar 5 and the second scissor bar 4. The second barrier bar sliding pivot 9 is located adjacent (at or near) the first end 5a of the barrier bar 5, as shown in Figures 3b and 3c. Again, the second sliding pivot 9 comprises a second barrier height adjustment slot 17b extending along part of the length of the barrier bar 5, at or near the first end 5a of the barrier bar. The second sliding pivot 9 also comprises a pivot shaft 20 that projects through an aperture in the second end 4b of the second scissor bar 4, the barrier height adjustment slot 17b, and an aperture in the first end 5a of the barrier bar to connect tge second scissor bar 4 to the barrier bar 5 in a sliding arrangement in which the pivot shaft 20 can move along the slot 17b and can rotate about its longitudinal axis within the slot.

Although the embodiment illustrated comprises only two sliding pivots, alternative embodiments may comprise four sliding pivots (one at each end of the attachment member and barrier member) and a fixed central pivot.

Each barrier height adjustment pivot slot for housing the sliding pivots may comprise an adjustable stopper (not shown) or other adjustment means to adjust the effective length of the pivot slot and to thereby allow the travel of the barrier and barrier bar (i.e. the height or the maximum fall/extension distance of the guard) to be adjusted and set. For example, a sliding rubber plug may be used as an adjustable stopper. Alternatively, a bolt may be inserted through the slot and tightened against the respective bar wit a nut to decrease the effective length of the pivot slot. Alternatively, the plug may be formed of another material and may be positioned within the pivot slot and may be adjusted and secured with a nut and screw bolt, or with any other suitable form for adjusting the effective length of the pivot slot.

In one form, the sliding and non-sliding pivot shafts 20 are formed by loose rivets located in an aperture of the respective framework bar. The sliding pivot shafts may alternatively be formed from two washers 18a, 18b bolted together and separated by a smaller washer 19, the smaller washer 19 being sized to fit inside the respective height adjustment slot 17a, 17b. The smaller washer has a thickness that is slightly greater than the thickness of the slot 17a, 17b, thereby relieving the friction between the bar comprising the slot and the two larger diameter washers on either side of the slot. A threaded bolt 22 passes through apertures in the washers 18a, 18b, 19 and is held in place with a threaded nut 31 that attaches to the end of the bolt 22. An exploded view of a sliding pivot shaft is shown in Figure 4.

In one form, the second scissor bar is pivotally attached to the upper bar via a first lengthened sleeve or separator bush and the first scissor bar is pivotally attached to the barrier bar via a second lengthened sleeve or separator bush (not shown), each bush being located between the respective bars and forming part of the pivot shaft. For example, as shown in Figure 4, a bush is used to extend the pivot shaft 20. The bush is placed next to a washer or flange of a pivot shaft as described above. A further washer is aligned with the bush and remaining pivot shaft so that the apertures of each part align with each other and with the pivot aperture. The first end of the first scissor bar is placed between the bush 23 and washer 21 so that an aperture at the first end of the scissor bar aligns with apertures in the pivot shaft arrangement. A threaded bolt passes through the apertures of the other component parts of the pivot shaft and is secured in place by a nut 31 to form the pivot shaft 20. In an alternative form, the three aligned washers 18a, 18b, 19 are replaced with a flanged bush comprising a hollow cylinder with flanges at each end, for example, as shown in Figures 6 and 7. In this form, the pivot shaft may comprise a flanged nut 20a that is threaded with a flanged bolt 20b to form a central cylinder of a first diameter bounded at each end by flanges of a second diameter larger than the first diameter. Figure 5 illustrates a front view of a sliding pivot shaft according to this aspect of the invention.

Alternative forms of non-sliding pivot shafts are also envisaged. These pivot shafts could take the form of a nut and bolt arrangement for example, or the flanged bush arrangement of Figures 6 and 7 could be used instead. In any pivot shaft arrangement used, it is important that the shaft is adapted so as not to interfere with the movement of the guard between an inactivated and an activated position and so as to couple the respective framework bars together in a way in which the bars can pivot relative to each other, but cannot twist.

Alternatively, the scissor arms may be formed with a clearance slot or recess 32 near the barrier bar pivot, as shown in Figures 3b and 3d. The clearance slot is located on an inwardly facing edge of the scissor arm. That is, when the clearance slot is located on a scissor arm near the barrier bar pivot for example, the clearance slot is positioned to face inwardly toward the attachment member when the guard is in the inactivated position. Similarly, if the clearance slot is located on a scissor arm near the upper bar pivot, the clearance slot is positioned to face inwardly toward the barrier bar when the guard is in the inactivated position. Preferably, the central pivot is closer to the second ends of the scissor bars than to the first ends. The effective lengths of each scissor arm (the maximum height that the extended scissor arm can reach away from the attachment member) may also be different depending on the location of each sliding pivot point in each barrier height adjustment slot. These features allow the pivot shafts 20 of the upper pivots 6, 8 to fit within the clearance slots 32 when the guard is in the inactivated position so that the guard can retract to a greater extent. Only one clearance slot is shown in the Figures, but optionally each scissor arm has a clearance slot near its second end. These features allow the framework members to align next to each other in the inactivated position, so that depth/height of the retracted guard is minimised when viewed from the front. In this form, when the guard is installed behind the front lip of a target shelf, the bottom edge of the barrier member may be substantially flush with the bottom edge of the shelf lip so that in the inactivated position, the guard is not clearly visible to someone looking at the front of the shelves.

Thus, in the embodiment illustrated in Figures la to 3c, the first end of the second scissor bar is pivotally attached to the second end of the upper bar at the upper bar non-sliding pivot 6 and the first end of the second scissor bar is pivotally attached to the first end of the barrier bar at the barrier bar sliding pivot 9. The first end of the first scissor bar is attached to the first end of the upper bar at the upper bar sliding pivot 8 and the second end of the first scissor bar is attached to the second end of the barrier bar at the barrier bar non-sliding pivot 7. The first scissor bar is attached to the second scissor bar at the central pivot 10, which is located at the centre of the scissor bars in the embodiment illustrated. This framework arrangement of bars and sliding and non-sliding pivots allows free vertical movement of the barrier bar while maintaining its horizontal level. Once activated, the scissor mechanism of this embodiment will extend toward the target shelf under the influence of gravity and/or under the influence of a drive system, until the barrier reaches its maximum extension at which time the guard is in the activated position.

In this embodiment, it is not necessary to use external energy, such as electrically, mechanically, or pneumatically driven mechanisms, to move the guard to the activated position, although such mechanisms may be used if desired and these mechanisms may be fitted to the guard as would be readily apparent to a person skilled in the art. For example, the drive system could push the barrier bar away from the upper bar by pushing one or both of the first ends of the scissor bars toward each other along the upper bar by utilising sliding pivots at these connection points.

In one form of the embodiment described above, the attachment member/upper bar is preferably an elongate reinforced bar that has an inverted generally U-shaped longitudinal cross-section having a central portion and to arms projecting from opposing sides of the central surface to form side portions. The central portion of the U is attachable to the underside of a shelf. The other components of the guard (for example, the first and second scissor bars and the barrier bar) slide into this U frame in a side-by-side arrangement when the guard is in the inactivated position to form a guard housing, as shown in Figures lc and Id. In this form, the attachment member is integral with the guard housing. Where the guard comprises a drive mechanism to drive the scissor bars away from the attachment point(s), the central portion of the U-shaped attachment member can be attached to the upper surface of the target shelf via at least one attachment point, so that the guard extends substantially perpendicularly upwards when in the activated position. Alternatively, a side portion of the U-shaped attachment bar may be attached to the front edge of a first shelf so that the barrier may extend above the level of the shelf (again, where the guard comprises a drive system), or the orientation of the guard may be reversed so that the barrier may extend substantially perpendicularly downwards (whether or not a drive system is used) below the level of the first shelf.

In an alternative form, the attachment member/upper bar is substantially planar and comprises attachment lugs or the like to attach to a shelf. Alternatively, the attachment member may have a substantially L-shaped profile, in which one arm of the "L" provides at least one attachment point for attaching to a shelf. In both embodiments, the other components of the guard lie adjacent to the upper bar when the guard is retracted in the inactivated position. The bars lie in series so that a first scissor bar lies adjacent to the upper bar and to the second scissor bar on its opposite side. The second scissor bar therefore lies between the first scissor bar and the barrier bar. An advantage of the scissor mechanism described is that the framework can fit into a relatively small space when the guard is retracted in the inactivated position, as shown in Figures 1 and lc. The scissor arms also provide additional protection to help prevent goods falling from the target shelf. Further, the scissor mechanism has a relatively low cost of manufacture. In one embodiment of the invention, as shown in Figures 3, 3c, and 3d, at least a portion of the framework, such as the underside of the barrier member 5, may be covered by a cushioning material 11, such as adhesive rubber, foam, or soft plastic, for example. The cushioning material absorbs at least some of the impact that occurs when items move from their normal position and strike the bar during vibrations. In another embodiment, the whole, or substantially the whole, of the barrier bar and/or the scissor arms and/or other framework may be covered by or coated in a cushioning material, such as foam or soft plastic for example, to reduce the likelihood of damage to items falling against the framework. The area of cushioning material, rubber, or foam may also provide for visual aesthetics. The framework is formed from a suitable material. In the preferred embodiment, the framework bars are formed from a metallic material, in particular an aluminium alloy. Alternative materials include wood or polymeric materials, such as plastics. Those materials may be reinforced. In another form, at least a portion of the framework may be made from a reinforced cushioning material. Each of the scissor bars and the barrier bar are preferably substantially rectangular and have a constant cross-section. Alternatively, the bars may have a substantially square, circular, or oval cross section. The bars may be solid or tubular. The bars may be specifically shaped, if required, to fit snugly underneath a shelf when the guard is inactivated. Alternatively, or additionally, the edges of the components forming the framework may be rounded to reduce the risk of damage to items that strike the framework.

The guard may optionally have wire, mesh, netting or fabric in between the scissor arms/cross bars, attachment bar, and barrier bar to stop smaller goods from falling through the spaces between those bars.

In particular, the guard with scissor mechanism may comprise a flexible material, such as netting, mesh, or fabric that extends between the attachment member/upper bar and the barrier bar to provide further protection to help prevent goods from falling from the target shelf when in the activated position. In the inactivated position, the flexible material may be folded or rolled into a retracted position and may unfurl or unroll when the guard moves to the activated position.

The upper bar can be fastened to existing standard holes in most existing shelving using screws, bolts, rivets, magnets (where there is a magnetic attraction between the magnets of the guard and a shelf), or any other suitable form of attaching the guard to a shelf. Alternatively, the upper bar may be adhered or otherwise suitably affixed to the shelving. Each point at which the upper bar or guard is attached to a shelf is an attachment point.

The guard may optionally be installed beneath a shelf having a downwardly projecting lip 101 at its front edge. Thus, when the guard is in the inactivated position, the guard will be concealed by the front lip of the shelf on which it is installed. Alternatively, the guard may be placed on the front edge of a shelf and can extend downwardly when activated. Where the barrier system or guard is placed on the front underside of a shelf or on the front edge of a shelf, facing downwardly, and the guard is activated, the barrier falls or extends to a predetermined height and helps to restrict goods from sliding forwards off the front of the target shelf immediately below that to which the guard is attached.

Thus, when the guard is in the activated position and attached to a shelf, the barrier will cover a portion of the vertical space (V) between that shelf and the adjacent target shelf above or below. Preferably, the barrier will cover a majority portion of the vertical space (V). Alternatively, the barrier may cover the entire vertical space (V).

The standard length of a preferred form of barrier system will be 895 mm long to match standard shelving units, but other lengths are also envisaged. However, it will be appreciated that the dimensions of the scissor bars can be easily scaled up or down lengthwise to fit various sized shelving units and side-ends of shelving units.

The guard may optionally be housed within its own guard housing 41, which may be formed from an attachment member having a U-shaped profile, as described above, or may be a different form of housing adapted to house substantially the whole of the guard when in the inactivated position and adapted to enable the guard to be attached to a shelf. The attachment member may be attached to the guard housing 41 or integral with the housing, as shown in Figures 9 to 11, and at least a portion of the rest of the framework of the guard is also substantially housed within the guard housing when the guard is in the inactivated position. The guard housing may also house or be attached to at least part of the actuator 12, as shown in Figures 9 to 11. Alternatively, the actuator may attach to the shelf to which the guard is to be attached or the actuator may attach to the guard itself. The guard housing is attachable to a shelf, as described above, and as illustrated in Figures 9 to 11. Preferably, the housing is attachable underneath the front edge of a shelf.

TRIGGER/ACTUATOR

The guard may operate using many different suitable forms of triggers/actuators to cause the guard to move from an inactivated position to an activated position. For example, the guard may comprise a passive actuator, a mechanically activated actuator, an electronically activated actuator, or an electro-mechanical actuator.

In an embodiment comprising a passive actuator, the actuator comprises a latch comprising a lock, which is biased by biasing means to a locking position, in which the lock projects from the latch and engages with the shelf guard to hold the guard in the inactivated position. By reversing the force imparted on the lock by the biasing means, the lock disengages from the shelf guard to allow the guard to move to the activated position.

In one embodiment, as shown in Figure 9, the actuator has biasing means 14 in the form of a spring 16 and a shaft 42. The actuator also comprises an actuator mount, for mounting the actuator to the shelf guard or to a shelf, and a projecting lock in the form of a ball 13. In this form, the spring 16 is coiled around the shaft 42, which is attached at one end to the actuator mount. The free end of the shaft 42 is concave and sized to receive the ball 13 against its surface. The free end of the spring 16 extends slightly beyond the free end of the shaft 42 and pushes against the ball 13. The pressure of the spring pushes the ball against the barrier bar of the guard that is located next to the actuator. In this way, the spring urges the ball 13 against the barrier bar 5 of the guard and holds the guard in the inactivated position under normal conditions due to friction forces between the ball and the guard. When vibrations or lateral movement, such as that experienced in an earthquake, reach a certain level, the friction between the ball and the barrier bar is overcome and the barrier bar drops. The force applied by the spring is adjustable by adjusting the position of the shaft to apply more or less load to the spring. It will be appreciated that applying more load to the spring will increase the level of vibrations required to activate the barrier. Similarly, decreasing the load to the spring will decrease the level of vibrations required to activate the barrier. In one embodiment of an actuator that is mechanically activated, as shown in Figures 13 to 17, the actuator comprises a medium sized ball 34, such as of a ball bearing, which rests inside a housing 24 having a concave floor, as shown in Figures 13 to 17. The upper inner contact surface 26 of the housing is also concave and comprises a pivoting lever 29 having pivot axles 27 that fit within pivot apertures 33 located at one side of the actuator housing. However, it is envisaged that the upper contact surface could alternatively be planar or of any other suitable form. A free end of the lever extends beyond the housing and includes an engagement catch 35. Optionally, the housing may comprise a fixed lid 44, spaced apart from the pivoting lever so as not to interfere with the pivoting ability of the pivoting lever.

In the inactivated position, the engagement catch 35 of the pivoting lever engages with an offset spring-loaded latch that has a lock 13 in the form of a projecting pin, as shown in Figure 18. When the engagement catch engages with the lock, the lock projects from the latch and rests beneath or against the barrier bar of the guard or projects through an aperture in the framework of the guard to hold the guard in the inactivated position. In a preferred embodiment, a contact surface of the engagement catch engages with a contact slot or recess 28 in the projecting lock 13. The engagement catch may be shaped with a concave contact surface to engage with the lock where the lock comprises a cylindrical pin. Alternatively, the contact surface of the engagement catch may be angular and orientated so that, in the inactivated position, the lock abuts the apex of the contact surface to hold the lock in a projecting locking position. Of course, the contact surface of the engagement catch may take many different shapes as would be readily apparent to a person skilled in the art and without departing from the scope of the invention.

In an earthquake, the ball 34 is caused to roll about inside the housing 24. As the ball rolls up the edges of the concave floor 26, the top of the ball 34 pushes against the upper contact surface of the housing, thus offsetting the pivoting lever 29 located above the ball. The lever 29 is caused to pivot upwardly and downwardly according to the movement of the ball, causing the engagement catch 35 to move upwardly and downwardly also. As the engagement catch moves up and down, its contact surface disengages from the projecting pin or lock 13. The spring-loaded lock 13 is biased toward a retracted position. Thus, as soon as the engagement catch disengages from the lock, the very sensitive spring-loaded latch causes the lock to retract from the barrier bar, allowing the barrier bar to fall. The offset-spring-loaded mechanism is based on the principals of a mousetrap using a very small force in one direction to release built up tension in another. In another embodiment, the actuator comprises a sensor in combination with a lock in the form of an electromagnet. The electromagnet may be attached to or integral with the attachment member, the guard housing or a shelf. The sensor may be attached to the locking mechanism of the actuator or it may be remote from the lock. The electromagnet has a current passing though it to create a magnetic force. The electromagnet includes a charged projection or lock that contacts a magnetic portion on the barrier member or on another part of at least a portion of the framework of the guard that is of an opposite charge to that of the lock to hold the guard in the inactivated position. This may be achieved by using a guard with a metal framework in which the guard connects with the lock, or by attaching a magnet to the guard at the point of contact with the lock. In this way, the lock holds the guard in the inactivated position using magnetic force, until the sensor senses a vibration of a predetermined level. At this point, the circuit to the electromagnet is cut, such as by using a switch that is caused to switch off at a certain level of vibration, or the polarity of the electromagnet is reversed. Once the electrical circuit to the magnet is cut or the polarity of the magnet is reversed, the magnetic attraction between the lock and the guard terminates and allows the guard to extend to the activated position.

In one form of an electro-mechanically activated actuator, an earthquake or vibration sensor is suitably installed onto a load bearing wall remote from the actuator lock, and preferably in a central location of the store or premises in which goods on shelves are to be protected by the shelf guard. The sensor has a (reverse) pendulum design to close an electrical circuit powered by a battery. Vibrations cause the conductive pendulum to move within a conductive housing or ring. When the pendulum touches the housing or ring, the circuit closes, causing a projecting arm to lock or disengage from the shelf guard, allowing the guard to extend to the activated position. In a preferred form, the sensor detects the faster travelling P waves of an earthquake before the damage causing S waves arrive. The sensor preferably comprises an adjustable sensitivity screw to adjust the position of the ring/housing with respect to the pendulum to assist in gaining the correct tolerances. This feature provides extra time for the barrier bars on each shelf to fall into position before the goods on the shelves begin to overcome friction and move.

The sensor has a switch to activate a 433 MHz radio frequency transmitter. Although the sensor has been described as being remote from the actuator lock, it is envisaged that each guard may comprise a sensor connected to the actuator lock without departing from the scope of the invention.

In another embodiment of an electro-mechanically controlled actuator, as shown in Figures 10 and 12, each shelving bay (two sides) or shelving unit in a store or other premises where the guard of the invention is to be used is fitted with a circuit featuring a power supply and a receiver, such as a 433 MHz radio frequency receiver. Each individual shelf is fitted with a 12v pull solenoid operably connected to each shelf guard and connected in parallel to the main shelving bay circuit. The pull solenoid has a projecting arm or lock 13 that engages with the barrier member of the guard to hold the guard in the inactivated position. A sensor (connected to the pull solenoid lock or located remotely from the pull solenoid) transmits a signal to the receiver when the sensor senses vibration of a predetermined magnitude. When a signal is received from the transmitter, the receiver then acts as a switch, which closes the circuit to drive each solenoid. Each solenoid retracts/pulls the respective lock 13 away from the respective barrier member, which in turn releases each barrier member. The transmitter is preferably set to send a 0.2 second, momentary signal burst.

The transmitter 43 may be located locally to the shelf guard or remotely from the guard. The control system may be set up so that one transmitter sends signals to a plurality of guards, as described above. Alternatively, each guard may have its own transmitter. In the preferred embodiment, one transmitter is used to control every shelf guard at the premises where a shelf guard is used. Signals that activate the actuator may be transmitted from a remote location via a wired or wireless method.

Using the radio frequency transceiver allows a single sensor to be used for an entire store or premises. The sensor is on the same frequency setting as each individual receiver in each shelving bay (2 sides) or shelving unit within 200m that would activate the solenoid in each shelf. In an alternative form, the sensors are electrically connected directly to each solenoid, which provides a lower cost alternative but may cause problems with the installation of the design. There is potential for either to be connected via an adaptor to mains power or to a solar panel, battery, or other power supply.

The locking mechanism of the actuator (for example, the projecting lock and the mechanical or electrical components that cause the lock to disengage the shelf guard when activated) in the embodiments above may be attached to an actuator mount for mounting the actuator to the shelf guard or to a shelf. The sensor may also be operably connected to the actuator mount or it may be remote from the mount.

The electrical and electro-mechanical embodiments are more reliable and consistent than the passive and mechanical embodiments. However, the passive and mechanical versions provide a cheaper alternative, which may be desirable to users who are willing to accept a degree of tolerance in terms of reliability in order to achieve a cheaper overall cost.

The guard of the invention may also be connected to an alarm system so that activation of the guard triggers an alarm simultaneously to alert personnel of danger when an earthquake is detected. The alarmed guard system may be set up so that an alarm sounds when the P waves are first detected.

Where the guard comprises powered components, such as a drive system, a pull solenoid, an electromagnet or an alarm, the guard may be powered using one or more batteries, mains power, a generator, or alternative self-contained power sources, such as solar panels. OPERATION

In use, the shelf guard may be placed on the front underside of each shelf in an inactivated position, as shown in Figure 4a, and preferably behind a downwardly projecting front lip at the front edge of the shelf. The attachment member or guard housing can be fastened to the shelf by screws, bolts, rivets, magnets, or adhesive for example, or by any other suitable form of affixing the guard to the shelf. The guard may be fastened to most existing shelving using existing standard holes in the shelving, and could be installed, tested and maintained by the store owner if necessary. In the inactivated position, an item in a storage area, such as on top of the shelving, is accessible and can be viewed without any obstruction, or at least without significant obstruction, from the guard. Items can be placed onto the target shelf or removed from the target shelf without being inhibited by the guard. During an earthquake or other significant vibration, the actuator will activate the guard to move from the inactivated position to the activated position. When the guard is in the activated position and attached to a shelf, the barrier will cover a portion of the vertical space between that shelf and the adjacent shelf above or below. In the embodiment shown, the barrier covers a majority portion of the vertical space. Alternatively, the barrier may cover the entire vertical space. Thus, in the activated position, the item(s) in the storage area of the target shelf is/are substantially inhibited from falling or being removed from the shelf, as shown in Figure 4b.

From the activated position, the shelf guard of the invention can easily be restored to the deactivated position by pushing it back into its locked position.

The shelf guard is suitable for small-medium retail outlets that include, but are not limited to, bottle stores, small supermarkets, minimarkets and cafes. However, the guard is also suitable for use anywhere that goods on shelves are to be protected. For example, the guard may be used in warehouses, libraries, large retail outlets, mobile homes, and houses.

In alternative embodiments, the framework of the guard comprises only an attachment member and a barrier member. The attachment member may be attached to or integral with a substantially "U shaped" guard housing as described above, or it may be attached to or integral with a different form of guard housing. In this form, as shown in Figure 19, the shelf guard comprises a flexible material, such as netting, mesh, or fabric. One edge of the flexible material is attached to the attachment member. An opposing edge of the material is attached to the barrier member, which may be in the form of a barrier bar (as shown) or it may be in the form of at least one weight. The guard comprises an actuator comprising a sensor, as described above, whereby the actuator causes the guard to move from the inactivated position to the activated position when the actuator senses a vibration of a predetermined magnitude. When activated, the actuator retracts or disengages a lock that holds the barrier member in the retracted position. The weight of the barrier member causes the barrier (comprising the barrier member and flexible material) to fall toward the target shelf immediately below. Thus the barrier forms a protective curtain along at least a portion of the target shelf to help inhibit goods falling from the target shelf. In the inactivated position, the flexible material may be folded or rolled and may unfold or unfurl from the inactivated position to the activated position.

The preferred embodiments described help prevent goods from falling off the front of a target shelf when the guard is attached to the front of a shelf. The preferred embodiments described are designed for situations in which there will be either another shelf at each of the side ends of the shelf to which the guard is attached or some other structure to restrict goods falling out the sides of the shelf. However, it is possible for both the front and sides of each shelf to be provided with a shelf guard according to the invention.

Alternatively, the guard may be in the form of a stretched "U" shape, in which the guard has an elongate central portion to at least partially surround the front of the target shelf in the activated position, and in which the guard has two shorter end portions extending substantially perpendicular to the central portion. The end portions are positioned to at least partially surround the ends of the target shelf when the guard is in the activated position. The flexible material may be netting, mesh, fabric, or the like, but could alternatively be a rubber or plastic form in a pleated or concertina arrangement that remains folded and substantially flat when the guard is in the inactivated position. One end of the flexible material is attached to the attachment member and the opposing end is attached to the barrier member. The barrier member may be a barrier bar or one or more weighted parts (where the barrier is to extend below a shelf). The guard may or may not include a scissor mechanism between the attachment member and barrier member, as described above. Similarly, the bar may or may not include other framework members, such as telescoping or flexible, resilient arms. When an actuator retracts a lock holding the pleated structure in the inactivated position, the pleated structure may extend to the activated position. The pleated structure may move under the force of gravity or by a drive system.

In alternative embodiments, the framework may comprise other suitable arrangements of extending arms. For example, the framework may comprise a moveable lattice formed of a plurality of interconnecting bars or scissor arms. The arms may be pivotally, and/or slidably connected to allow for retraction to form the inactivated position and extension to form the activated position. Other alternative frameworks include one or more telescopically extending and retracting arms that is/are connected to the attachment member. The arm(s) is/are adapted to retract in the inactivated position and to extend away from the attachment member in the activated position, when caused to move by the actuator. The at least one telescopic arm may extend perpendicularly from the attachment member or may be angled from the attachment member. Where two angled telescopic arms are used, the arms may cross each other, in a similar arrangement to a scissor arrangement, but without a pivot connection between the arms. Alternatively, the framework may comprise an attachment member with at least one flexible and/or resilient arm. In this form, at least one elongate arm is attached to one end of the attachment member. The arm is biased to project away from the attachment member. Preferably, one arm is attached at each end of the attachment member. The arm(s) may be held against or close to the attachment member with a retractable lock mechanism, so that in the inactivated position, the arm(s) lie(s) substantially parallel to the shelf to which the guard is attached. When a vibration of a predetermined magnitude occurs, the lock retracts and disengages from the arm(s). The resilient nature of the arm(s) causes the arm(s) to spring back to the biased position, extending away from the attachment member. In this embodiment, each arm is attached to a sheet of flexible material that is also attached to the attachment member. Thus, as the arms extend away from the attachment member, the flexible material is pulled taught to provide a screen that substantially surrounds the target shelf. Alternatively, the guard may include a plurality of resilient, flexible arms that form a fence to substantially surround the target shelf when in the activated position.

It is envisaged that in some embodiments, the barrier member need not be a barrier bar or weighted member, but could instead be the front edge of a barrier formed from a flexible material and one or more extending arms (the front edge being the edge farthest from the attachment member when in the activated position). Alternatively, the barrier member may comprise the distal ends of a plurality of arms, the distal ends of the arms being those furthest from the attachment member to which the arms are connected.

Thus, the barrier member may be operably connected to the attachment member through scissor arms (where the guard uses a scissor mechanism), other forms of extending arms, a flexible material, a pleated material, or another suitable intermediary that allows the barrier member to retract toward the attachment member and to move away from the attachment member to form a barrier that substantially surrounds a target shelf.

In any of the above embodiments, the actuator lock may engage with any suitable member of the framework of the guard in any way that allows the lock to hold the guard in an inactivated position. For example, the actuator lock may engage with the barrier member or with scissor arms or other arms of the guard. The lock may abut against a framework member to hold the guard in position under friction forces or the lock may extend beneath a member of the guard, such as the barrier member, to hold the guard in the retracted position, or the lock may extend through an aperture in any suitable member of the guard, such as through an aperture in a scissor arm, other arm, or barrier member.

Preferred embodiments of the invention have been described by way of example only and modifications may be made thereto without departing from the scope of the invention.

For example, in the embodiment described, the guard is typically placed on the front underside of each shelf. In an alternative embodiment, the guard may be attached on the upper surface of a shelf and may rise from the inactivated position to the activated position using a drive means as described above. In another alternative embodiment, the guard may be placed on the front edge of a shelf and may either extend below the shelf or rise above the shelf, depending on its operation and orientation, to move from an inactivated position to an activated position. Further, in the passive version of the actuator, the spring-loaded ball acts against the barrier bar to maintain the barrier in the inactivated position. In an alternative embodiment, the spring-loaded ball may act against either the first scissor bar or the second scissor bar. Further, the guard may comprise more than one spring-loaded ball. Further, the lock in the mechanical and electronic embodiments may act against the barrier bar or the first or second scissor bars. The mechanical, electro-mechanical and electronic embodiments may comprise more than one lock.

The guard may comprise any of the barriers described above in combination with any of the suitable triggers mentioned above and together with any of the suitable sensors mentioned above. For example, the guard may comprise a barrier in the form of a net, the actuator may be a mechanical actuator and the sensor may be a passive sensor. In another example, the guard may comprise a barrier in the form of a framework and fabric, the actuator may be an electromagnetic switch and the sensor may be a pendulum-included circuit.