Field of the invention

The present invention relates to a latch system. More particularly, the present invention relates to a latch system for use in retaining a movable closure in a closed position across an opening in a fixed.

Background

Typical latch systems used to hold non-residential movable structures - such as gates, door, windows, etc. - in closed positions employ simple mechanisms. By way of example, one common latch system for a farm gateway has a latching member, and a catch that are both secured to one of the gate posts. The latching member has a chain with a retaining element at one end, and the other end secured to the post. When the gate is in the closed across the gateway, the retaining element is passed through an opening in the gate so that the chain extends through that opening, and the retaining element is engaged with the catch.

In some examples of these simple latch systems, disengagement of the retaining element from the catch often requires a two-step operation. This provides the latch system with excellent reliability, in that once the latch system is used to latch the movable structure in its closed position, the chance of the movable structure being unlatched without human interaction (for example, by wind or livestock moving the structure or latch system components) is negligible.

Monitoring of the latch systems requires visual inspection. By way of example, a farmer wanting to know whether or not a gate is latched requires the farmer to visually inspect the gate and latch system. This can be a time-consuming endeavour, particularly for a farmer with a large property that has many gates.

There is a need to address the above, and/or at least provide a useful alternative. Summary

There is provided a latch system for use in retaining a movable closure, that is mounted at an opening in a fixed structure, in a closed position across the opening, the latch system comprising: a catch that has a body with at least one mounting element for mounting the catch, and a retaining element; a latching member having an engaging portion that is releasably engageable with the retaining element, the latching member being mountable to the movable closure or part of the fixed structure that is adjacent the movable closure, the latching member being movable between: a latching configuration in which the engaging portion is engaged with the retaining element of the catch to retain the movable closure in the closed position, and one or more released configurations in which the engaging portion is disengaged from the retaining element so that the movable closure is movable with respect to the opening to thereby allow passage through the opening; and an electronic circuit that includes: a sensing element that is mounted internally within the body of the catch and proximate the retaining element, the sensing element being configured to adopt an active state when the latching member is in the latching configuration, and to adopt an inactive state when the engaging portion is disengaged from the retaining element, each of the active and inactive states corresponding with a distinct electronic output from the sensing element, a data transmitter for transmitting wireless electronic signals, a processor that is in electronic communication with the sensing element and the data transmitter so as to receive electronic outputs from the sensing element, and provides instruction to the data transmitter in response to a change between the active and inactive states, and a power supply for providing electrical power in the electronic circuit. In some embodiments, the mounting element is configured for mounting the catch on a part of the fixed structure adjacent the opening.

In some alternative embodiments, the movable closure includes a first movable closure portion and a second movable closure, both of which are mounted at the opening, the first and second movable closures portions cooperating to close the opening in the fixed structure, wherein the mounting element is configured for mounting the catch on one of the first or second movable closure portions, and wherein the latching member is able to retain both the first and second movable closure portions in the closed position across the opening when the latching member is in the latching configuration.

Preferably, the sensing element is a reed-type switch with a normally open state that corresponds with an inactive state, and a closed state that corresponds with an active state, wherein the switch adopts the closed state when the latching member is engaged with the retaining element of the catch. In some embodiments, the sensing element is a non-contact reed switch.

In at least some embodiments, the engaging portion of the latching member is made of a ferromagnetic material, the body of the catch is made of one or more substantially non-ferromagnetic materials, and the sensing element is configured to: adopt the active state when ferromagnetic material is within an activation distance of the sensing element, and adopt the inactive state when there is no ferromagnetic material within the activation distance.

In certain preferred embodiments, the sensing element is a non-powered ferromagnetic switch. In certain embodiments, the body of the catch is made of aluminium. In some alternative embodiments, the body of the catch is made of material that includes plastic.

In some embodiments, the engaging portion of the latching member has a drop pin, and the retaining element is an aperture that is defined by the body, wherein when the latching member is in the latching configuration the drop pin extends through the aperture.

Preferably, the body has a mounting portion , and a plate that projects outwardly with respect to the mounting portion, wherein the aperture is formed in the plate.

The body can further include a central section that is beneath the plate, the central section having a front face that is disposed horizontally between the aperture and the mounting portion, and wherein the sensing element is disposed within the central section and adjacent the aperture.

In certain embodiments, the body can further include one or more wings that project from the central section, and wherein at least one of the mounting elements is located in each wing.

The mounting portion can define a rearwardly oriented mounting surface that faces the part of the fixed structure adjacent the opening when the catch is mounted on the fixed structure. Preferably, each mounting element is a through hole, and the latch system includes one or more fasteners that are to pass through the through holes for use in retaining the catch to the fixed structure.

Preferably, the sensing element is positioned within the body of the catch such that when the retaining element is engaged with the catch, the separation of the sensing element from the engaging portion is less than 80% of the activation distance. More preferably, the sensing element is positioned within the body of the catch such that when the retaining element is engaged with the catch, the separation of the sensing element from the engaging portion is less than 25% of the activation distance.

In some embodiments, the latch system further comprises a housing within which selected components of the electronic circuit are housed, and wherein: the housing is integral with the body of the catch, the housing is supported by the body of the catch, or a portion of the housing is defined by the body of the catch.

Preferably, the housing is integral with the mounting portion, the housing is supported by the mounting portion, or a portion of the housing is defined by the mounting portion.

In such embodiments, the electronic circuit includes electrical wires that interconnect the sensing element and the processor, wherein the electrical wires extend through the body of the catch and into the housing.

Alternatively or additionally, the body of the catch defines a cavity within which components of the electrical circuit are disposed.

In some alternative embodiments, the latch system further comprises a housing within which selected components of the electronic circuit are housed, and wherein the electronic circuit includes electrical wires that interconnect the sensing element and the processor, the electrical wires extending between the body of the catch and the housing.

The electronic circuit can include one or more electrical connectors that are positioned between the sensing element and the processor, whereby the electrical connectors releasably connect the sensing element into the electronic circuit.

In at least some embodiments, the data transmitter is configured to transmit wireless signals in sub-gigahertz radio frequency bands. In one form, the data transmitter is configured to transmit wireless signals in accordance with the LoRaWAN communication protocol. Preferably, the data transmitter is configured to transmit wireless signals in accordance with the IEEE 802.11ah wireless networking protocol, as published in 2017.

In one alternative form, the data transmitter is configured to transmit wireless signals in accordance with the Narrow Band Internet of Things (NB IoT) communication protocol.

In another alternative form, the data transmitter is configured for direct-to-orbit satellite transmission.

There is also provided a catch for a latch system that is suitable for use in retaining a movable closure, that is mounted at an opening in a fixed structure, in a closed position across the opening, the catch comprising: a body with at least one mounting element for mounting the catch; a retaining element; and an electronic circuit that includes: a sensing element that is mounted internally within the body of the catch and proximate the retaining element, the sensing element being configured to adopt an active state when a latching member of the latch system is in the latching configuration, and to adopt an inactive state when an engaging portion of the latching member is disengaged from the retaining element, each of the active and inactive states corresponding with a distinct electronic output from the sensing element, a data transmitter for transmitting wireless electronic signals, a processor that is in electronic communication with the sensing element and the data transmitter so as to receive electronic outputs from the sensing element, and provides instruction to the data transmitter in response to a change between the active and inactive states, and a power supply for providing electrical power in the electronic circuit.

In some embodiments, the mounting element is configured for mounting the catch on a part of the fixed structure adjacent the opening.

In some alternative embodiments, the movable closure includes a first movable closure portion and a second movable closure portion, both of which are mounted at the opening, the first and second movable closure portions cooperating to close the opening in the fixed structure, wherein the mounting element is configured for mounting the catch on one of the first or second movable closure portions.

Preferably, the sensing element is a reed-type switch with a normally open state that corresponds with an inactive state, and a closed state that corresponds with an active state, wherein the switch adopts the closed state when the latching member is engaged with the retaining element of the catch. In some embodiments, the sensing element is a non-contact reed switch.

In at least some embodiments, the body of the catch is made of one or more substantially non-ferromagnetic materials, and the sensing element is configured to: adopt the active state when ferromagnetic material is within an activation distance of the sensing element, and adopt the inactive state when there is no ferromagnetic material within the activation distance.

In certain preferred embodiments, the sensing element is a non-powered ferromagnetic switch.

In certain embodiments, the body of the catch is made of aluminium. In some alternative embodiments, the body of the catch is made of material that includes plastic. In some embodiments, the retaining element is an aperture that is defined by the body, wherein a drop pin of the latching extends through the aperture when the latching member is in the latching configuration.

Preferably, the body has a mounting portion , and a plate that projects outwardly with respect to the mounting portion, wherein the aperture is formed in the plate.

The body can further include a central section that is beneath the plate, the central section having a front face that is disposed horizontally between the aperture and the mounting portion, and wherein the sensing element is disposed within the central section and adjacent the aperture.

In certain embodiments, the body can further include one or more wings that project from the central section, and wherein at least one of the mounting elements is located in each wing. The mounting portion can define a rearwardly oriented mounting surface that faces the part of the fixed structure adjacent the opening when the catch is mounted on the fixed structure. Preferably, each mounting element is a through hole, and the latch system includes one or more fasteners that are to pass through the through holes for use in retaining the catch to the fixed structure.

Preferably, the sensing element is positioned within the body of the catch such that when the retaining element is engaged with the catch, the separation of the sensing element from the engaging portion is less than 80% of the activation distance. More preferably, the sensing element is positioned within the body of the catch such that when the retaining element is engaged with the catch, the separation of the sensing element from the engaging portion is less than 25% of the activation distance.

In some embodiments, the catch further comprises a housing within which selected components of the electronic circuit are housed, and wherein: the housing is integral with the body, or the housing is supported by the body. The electronic circuit includes electrical wires that interconnect the sensing element and the processor, and wherein the electrical wires extend through the body of the catch and into the housing. Alternatively, the electrical wires can extend between the body of the catch and the housing.

The electronic circuit can include one or more electrical connectors that are positioned between the sensing element and the processor, whereby the electrical connectors releasably connect the sensing element into the electronic circuit.

In some alternative embodiments, the body of the catch defines a cavity within which components of the electrical circuit are disposed.

Brief description of the drawings

In order that the invention may be more easily understood, embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1: is a schematic view of a latch system according to a first embodiment of the present invention, showing the latching member in an unlatched state;

Figure 2: is a schematic view of the latch system of Figure 1, showing the latching member in its latched state;

Figure 3: is an upper perspective view of the catch of the latch system of Figure 1;

Figure 4: is a front view of the catch shown in Figure 3;

Figure 5: is a bottom view of the catch shown in Figure 3;

Figure 6: is a block diagram of an electronic circuit of the latch system of Figure i;

Figure 7: is a schematic top view of the latch system of Figure 1 installed on gate post that defines a gateway within a fence; Figure 8: is an enlarged view of Region A in Figure 7; Figure 9: is a schematic illustration of a wireless network including the latch system of Figure 1, in a released configuration, a wireless router, and a mobile device showing data indicative of the latch system status;

Figure 10: is a schematic illustration of a wireless network including the latch system of Figure 1, in a released configuration, a wireless router, and a mobile device showing data indicative of the latch system status;

Figure 11: is a schematic view of a latch system according to a second embodiment of the present invention, showing the latching member in an unlatched state;

Figure 12: is a schematic view of the latch system of Figure 11, showing the latching member in its latched state;

Figure 13: is a schematic top view of the latch system of a third embodiment of the present invention, the latch system being installed on a pair of gates that form a movable closure within a fence;

Figure 14: is an elevation view of the latch system of Figure 13, as viewed in in the direction indicated by Arrow X, showing the latch system in a latching configuration; and

Figure 15: is an elevation view of the latch system of Figure 13, as viewed in in the direction indicated by Arrow Y, showing the latch system in a released configuration.

Detailed description Figures 1 to 10 show a latch system 10 that is suitable for use in retaining a movable closure, that is mounted at an opening in a fixed structure, in a closed position across the opening. For example, the system 10 can be used for retaining a farm gate G across a gateway that is defined by an agricultural wire fence. In this example, the farm gate G is the movable closure, wire fence F is the fixed structure. Gate posts P of the fence F define the opening. Figures 7 and 8 illustrate schematically the latch system 10 installed on one of the gate posts P, and is usable to retain the gate G in the closed position, thereby providing a barrier to passage through the opening.

The latch system 10 has a catch 12, and a latching member that is mountable either to the movable closure, or to part of the fixed structure adjacent that is adjacent. In this particular example, the latching member has a chain 14 that is to be anchored at one end, either to a gate post P (as in the example of Figures 7 and 8), or alternatively to the gate G itself. At the opposing end of the chain 14 is an engaging portion, which in this embodiment is a drop latch 16, with a drop pin 18, and a loose ring 20 that restricts unlatching of the drop pin 18.

As shown particularly in Figure 4, the catch 12 has a body 22 with a retaining element, and mounting element for mounting the catch 12 on a part of the fixed structure adjacent the opening. In this particular embodiment, the retaining element is in the form of an aperture 24 formed in a plate 26 of the body 22.

The drop latch 16 is releasably engageable with the catch 12 by passing the drop pin 18 downwardly through the aperture 24. When the drop pin 18 has passed sufficiently through the aperture, the loose ring 20 falls against the drop pin 18 to inhibit unintentional removal of the drop latch 16 from the catch 12. When the drop latch 16 is engaged with the catch 12 in this way, the latching member is in a latching configuration. As will be appreciated by the person skilled in the art, for the embodiment of Figure 1 the chain 14 must extend through a small opening in the gate G so as to retain the gate G in a closed position across the gateway in the wire fence.

To release the drop latch 16 from the catch 12, the loose ring 20 is lifted away from the drop pin 18, so as to enable the drop pin 18 to be withdrawn from the aperture 24 in the plate 26. Once the drop pin 18 is withdrawn in this way, the drop latch 16 is disengaged from the plate 26, and so the latching member is in released configurations. The gate G is able to be opened to allow passage through the gateway. In Figures 1 and 9, the catch 12 and drop latch 16 are shown in released configurations. In Figures 2, 7, 8 and 10, the catch 12 and drop latch 16 are shown in latching configurations.

Figure 7 illustrates the gate G in the closed position. In this example, the gate G is supported on one of the gate posts P by a pivot mount (such as a gudgeon pin and strap mounting set). When the catch 12 and drop latch 16 are in released configurations, the gate G can swing out of the closed position, as indicated in Figure 7 by broken arrows S.

The latch system 10 includes a housing 28, and an electronic circuit 30, components of which are housed within the housing 28. The electronic circuit 30, which is illustrated schematically in Figure 6, includes a sensing element 32, a processor 34, a data transmitter 36, and a power supply 38 for providing electrical power in the electronic circuit 30.

Within the latch system 10, the sensing element 32 is mounted internally within the body 22 of the catch 12, and proximate the aperture 24 in the plate 26, as indicated in Figures 4 and 5. The sensing element 32 is configured to adopt an active state when the drop latch 16 is in the latching configuration, and to adopt an inactive state when the drop latch 16 is disengaged from the catch 12. Each of the active and inactive states correspond with a distinct electronic output from the sensing element 32.

One commercially available form of drop latch 16 has the drop pin 18 made of steel. In one form, the sensing element 32 is a non-powered ferromagnetic switch (for example, a magnetic reed switch) that has a normally open state that corresponds with the inactive state, and a closed state that corresponds with the active state. As will be appreciated by those skilled in the art, magnetic reed switches have an activation distance, which is the limit of separation between the switch and ferromagnetic material for which the magnetic interaction between the magnet within the reed switch and the ferromagnetic material enables the switch to adopt its closed state. As will also be appreciated, the material properties and geometry of the "target" affects the activation distance. The activation distance is also known as the "sensing range". Thus, the sensing element 32 is configured to:

- adopt the active state when the drop latch 16 is in the latched configuration (with the drop latch 16 engaged with the catch 12 as describe above), as the drop pin 18 is within an activation distance of the sensing element 32, and

- adopt the inactive state when the drop latch 16 is in released configurations (because the drop latch 18 is not in the aperture 24 and there is no ferromagnetic material within the activation distance of the sensing element 32.

To enable the sensing element 32 to operate in this manner, the body 22 of the catch 12 is made of non-ferromagnetic materials. In the embodiment illustrated in Figures 1 to 11, the body 22 of the catch 12 is made of aluminium.

In this example, the magnetic reed switch adopts the closed state when the drop pin 18 is within an activation distance of the order of 5 to 8 mm of the switch. The configuration of the catch 12 (as described in further detail below) and the position of the sensing element 32 can enable some free play of the drop pin 18 within the aperture 24, without the sensing element 32 incorrectly adopting the inactive state.

The processor 34 is in electronic communication with the sensing element 32 so as to receive electronic outputs from the sensing element 32. To this end, the electrical circuit 30 includes wires 40 that interconnect the sensing element 32 with the processor 34. As will be appreciated, in embodiments in which the sensing element is switch that alters its state when the drop latch 16 is in the latching configuration, current flow through the wires 40 is dependent on the closed / open state of the switch. The processor 34 can be configured to monitor for either a voltage change in the part of the electrical circuit 30 that includes the sensing element, or for current flowing through the wires 40. The data transmitter 36 is configured for transmitting wireless electronic signals. The processor 34 is in electronic communication with the data transmitter 36, and provides instruction to the data transmitter 36 in response to a change between the active and inactive states. Upon receipt of instruction from the processor 34, the data transmitter 36 broadcasts wireless electronic signals for receipt within a network, as described in further detail in reference to Figures 9 and 10 below.

The power supply 38 can include a battery so that the latch system 10 is not dependent on connection to an external power supply. This has the benefit of enabling the system 10 be mounted in remote locations.

As shown in Figures 1, 2 7, and 8, the latch system 10 can be arranged with the wires 40 enabling the housing 28 to be positioned away from the gateway. This has the benefit of allowing the housing 28 to be mounted in a position that is removed from the gateway, and less susceptible to damage from traffic through the gateway.

As shown in Figures 3 to 5, the body 22 of the catch 12 has a mounting portion 42. In this example, the mounting portion 42 defines a rearwardly oriented mounting surface 43 that is to face the gate post P adjacent the gateway, when the catch 12 is mounted on the post P. The plate 26 projects outwardly with respect to the mounting portion 42, and also away from the mounting surface 43, as shown most clearly in Figure 5.

The body 22 further has a central section 44 that is beneath the plate 26, and a pair of wings 46 that project laterally from the central section 44. The central section 44 includes a front face 48 that is disposed horizontally between the aperture 24 and the mounting surface 42. The sensing element 32 is disposed within the central section 44 and adjacent the aperture 24, as shown in Figures 4 and 5.

The mounting elements are located in the wings 46 of the body 22. To this end, each mounting element is a through hole 50 formed in a respective one of the wings 46. As indicated in Figures 7 to 9, in this embodiment the latch system 10 includes fasteners 50 that pass through the through holes 50 and retain the catch 12 to the gate post P.

In some embodiments, the data transmitter 36 is configured to transmit wireless signals in sub-gigahertz radio frequency bands. Depending on terrain factors, mounting conditions of the data transmitter 36 and data receiver, the transmission power, etc. data signals can be transmitted large distance; for example of the order of up to 10 kilometres. In one example, the data transmitter is configured to transmit wireless signals in accordance with the IEEE 802.11ah wireless networking protocol, as published in 2017. Benefits of this networking protocol are the extended range, and the licence free spectrum band.

Figures 10 and 11 show wireless area network 60 that includes the latch system 10, and a LoRaWAN wireless gateway 62. As described above, the status of the latching member (that is, whether in the latching configuration or a released position) is inferred by the active / inactive state of the sensing element 32. The processor 34 and data transmitter 36 operate to broadcast wireless signals that are representative of the status of the latching configuration. In certain embodiments, the latching system 10 can broadcast wireless electronic signals when there is a change of status (as sensed by the sensing element 32) and/or at fixed intervals. The wireless gateway 62 receives the wireless electronic signals from the latching system 10.

In some embodiments, the wireless gateway 62 can be connected to a separate network such that data transmitted by the latching system 10 is available for display and/or interpretation to provide information regarding the status of latching member. For example, the wireless gateway 62 can pass the data received from the latching system 10 to an internet enabled server (not shown), that is also connected to a mobile device 64 and/or a computer. As indicated in Figures 9 and 10, information regarding the status of the latching member can be displayed on a dashboard on the screen of the device 64 and/or the computer. It will be appreciated that the wireless signal transmission protocol needs to only match that of the wireless network within which the latch system 10 communicates. As such the wireless communication components of latch system according to any embodiment is selected to match the desired wireless network. The selection of the wireless network depends on various factors.

Figure 9 shows that latch system 10 with the drop latch 16 disengaged from the catch 12. Accordingly, the dashboard shown on the mobile device 64 contains information that identifies the gateway by user defined terms (as "Entrance Yards", in this example), and shows information representative of the latch member status. To this end, in this example and with respect to Figure 9, the latch member is in a released configuration. Accordingly, the dashboard includes an icon of the gate, and also the word "OPEN". The icon indicates that gate is in an open position.

Figure 10 shows that latch system 10 with the drop latch 16 engaged with the catch 12. In this example and with respect to Figure 10, the latch member is in the latched configuration. Accordingly, the dashboard includes an icon of the gate, and also the word "CLOSED". The icon indicates that gate is in the closed position.

In each of Figures 9 and 10, the dashboard also includes information that shows when the last recorded change of latch member status occurred.

As will be appreciate, the latch system can provide a farmer with the ability to ascertain information representative of the gate condition (that is, closed and latched, or unlatched) without having to visually inspect the gate and latching system itself.

In some situations, a latch system that is substantially similar to that illustrated in Figures 1 to 10 can be used for retaining a pair of farm gates across a gateway in an agricultural wire fence. In this example, both farm gates are movable structures, and are brought into their closed positions across the gateway. With the catch mounted on one of the gates, and the latching member on either gate, the two gates can be retained by the latch system in their closed positions by placing the latching member in the latching configuration.

Figures 11 and 12 show a latch system 110 according to a second embodiment. Parts of the latch system 110 that are the same or similar to parts of the latch system 10 have the same reference numbers with the prefix "1" and for succinctness, will not be described again.

The principal difference between the latch system 10 and the latch system 110 is in the style of engaging portion of the latching member, and correspondingly the style of the catch.

The latch system 110 has an engaging portion that is a ring latch 116. The catch 112 has a body that is in the form of a shank 170 with a right-angle bend 172 formed between the two ends of the shank 122. Further, the catch 112 has a retaining element that is in the form of a button head 174 at the outer end of the shank 124. Between the right-angle bend 172 and the inner end of the shank 124 is an external thread 176. The external thread 176 forms the mounting element of the catch 112.

In this particular embodiment, the latching member is in the latching configuration when the ring latch 116 is passed over the button head 174 and resting on the shank 170, as shown in Figure 12.

In one example, the catch 112 is made of non-ferrous material, such as a glass- reinforced plastics material. The sensing element (not shown) of the latch system 110 can be moulded internally within the shank 170 of the catch 112, between the button head 174 and the external thread 176. Accordingly, the sensing element of this embodiment can also be a non-powered ferromagnetic switch.

Figures 13 to 15 show a latch system 210 according to a third embodiment. Parts of the latch system 210 that are the same or similar to parts of the latch system 10 have the same reference numbers with the prefix "2" and for succinctness, will not be described again.

In the example of Figure 13, the movable closure includes first and second movable closure portions. In this particular embodiment, the first and second movable closure portions are in the form of farm gates Gi, G2 that are mounted at an opening in a fence F. Gate posts P of the fence F define the opening. Each of the gates Gi, G2 is pivotally mounted on a respective gate post P by a pivot mount. Figure 13 illustrates the gates Gi, G2 in the closed position. As will be appreciated, the gates Gi, G2 cooperate to close the opening in the fence F.

When in the latching configuration, the latch system 210 secures the two gates Gi, G2 to each other, thereby providing a barrier to passage through the opening. Figure 14 illustrates the latch system in its latching configuration. When in the released configurations, each gate Gi, G2 can swing out of the closed position, as indicated in Figure 15 by broken arrows Si, S2.

The latch system 210 has a catch 212, and a latching member that is able to engage with the catch 212 to retain the gates Gi, G2 in the closed position.

As shown particularly in Figures 14 and 15, the catch 212 has a body 222 with a retaining element. The body 222 has mounting elements, which in this embodiment are in the form of mounting holes 250. In this particular embodiment, the latch system 210 includes mounting clamps 280 that are secured to the body 222 via the mounting holes 250. The mounting clamps 280 anchor the body 222 to the peripheral frame of one of the gates Gi.

The latching member has a chain 214 that is to be anchored at one end to the gate G2. At the opposing end of the chain 214 is a drop latch 216. In this particular embodiment, the latch system 210 includes a second mounting clamp 282 that anchors the chain 214 to the frame of gate G2. The body 222 includes a mounting portion 242 in which the mounting elements are formed. The retaining element is in the form of an aperture 224 formed in a plate 226 of the body 222. The plate 226 projects outwardly from the mounting portion 242, as shown in Figure 14. The drop latch 216 engages with the catch 212 in the same manner as the drop latch 16 and catch 12 of the latch system 10.

The latch system 210 includes a housing 228 within which selected components of the electronic circuit are housed. In this particular embodiment, the housing 228 is supported by the mounting portion 242 of the catch 212.

Electrical wires that interconnect the sensing element with the processor extend through the mounting portion 242 into the housing. As will be appreciated, an advantage of this particular embodiment is that the electrical wires that interconnect the sensing element with the processor are not exposed to damage, for example, from the elements, animals, or incidental contact.

In the embodiment illustrated in Figures 14 and 15, the plate 226 is on the opposing side of mounting portion 242 to the housing 228. Flowever, in some alternative arrangements, the plate 226 and housing 228 can be on the same side of the mounting portion 242.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.