Electromechanical Latch Assembly

This invention relates to a latch assembly for use with a gate to releasably hold it in a closed position relative to a fence. More specifically the assembly includes an actuator being operable from a first and second height to release the gate, whereby the second height is lower than the first height. Latch assemblies of the foregoing kind have an application in relation to gates in swimming pool fences and it will be convenient to hereinafter describe the invention with reference to this particular application. It should be appreciated however that the latch assembly may have other applications for use with gates on other forms of fence, and even for use on doors.

The function of pool fences is to keep unauthorised persons, such as unsupervised children from gaining access to the pool. A gate is normally included to provide a convenient access point to the fenced area. A latch assembly is often used to keep the gate secured in a closed position. One form of latch assembly known to the applicant includes a hand engageable pull knob for moving a latch bolt from an operative position where it secures the gate in a closed position, to an inoperative or release position whereby the gate can be moved to an open position. The latch assembly is often located on the outside of the gate post with the pull knob located at a height which is beyond the reach of most children but still within reach of standing adults. This location of the pull knob can deny access to some authorised persons, such as shorter adults or disabled persons in wheel chairs.

Attempts have been made to improve access for authorised persons denied access by existing latch assemblies, while maintaining security against access by unauthorised persons. This has included modifying the pull knob type latch assembly by providing a latch release means at a lower location on the gate, the operation of which is controlled by a key. Naturally only authorised users are provided with an access key. The key is inserted into the keyway of the latch release means, which permits the authorised user to manually move a cam to move the latch bolt to the release position. Whilst this latch assembly

addresses some of the problems encountered by shorter adults, disabled persons in wheel chairs still have some difficulty in operating this form of latch assembly. In particular the insertion of the key into the key way and moving of the cam while controlling a wheel chair can be difficult. It can also be difficult keeping the latch bolt in the release position to open the gate while manoeuvring the wheel chair.

It would be advantageous to provide a latch assembly that provided improved access to authorised persons, in particular it would be advantageous to provide improved access to authorised persons with disabilities.

According to this invention there is provided a latch assembly for use with a gate located in a fence, the latch assembly including, a latch bolt being beatable in an operative and an inoperative position to hold and release respectively the gate from being moved from a closed position, a first latch release means having hand engageable means for facilitating manual movement of the latch bolt from the operative position, the hand engageable means being located in use at a first height accessible by a standing adult, a second latch release means having electromagnetic means which when operable moves the latch bolt from the operative position and holds it in the inoperative position, a key tag reader being operable to read a signal from a user's key tag, processing means being operable to processes the signal read by the key tag reader and to confirm the read signal is an authorised signal, activation means being operable to render the electromagnetic means operable when the processing means confirms the read signal is authorrised, the key tag reader being located in use at a second height which is lower than the first height so as to be accessible by a seated adult.

It should be appreciated that by locating the key tag reader at a height accessible by a seated adult that the latch assembly provides improved access to authorised persons. It should also be appreciated that the ability of the electromagnetic means to move the latch bolt from the operative position and to hold the latch bolt in the inoperative position makes the latch assembly easier to use.

It is preferred that the activation means includes a power source in a circuit connected to the electromagnetic means, the circuit having a switch that when in a closed position supplies power to the electromagnetic means to render the electromagnetic means operable. The activation means may include a transformer which receives power at 240 volts and converts the power to 12 volt for supply to the electromagnetic means. Alternatively the power source may supply power at 12 volts.

It is preferred that the electromagnetic means includes a coil of wire which creates an electromagnetic field when the electromagnetic means is rendered operable, the electromagnetic means also having at least one permanent magnet that is moved relative to the coil of wire when the electromagnetic means is operable to move the latch bolt from the operative position. It is further preferred that the electromagnetic means includes at least one first permanent magnet that moves towards the coil and at least one second permanent magnet that moves away from the coil when the electromagnetic means is rendered operable, the at least one first permanent magnet having a polarity that is oriented oppositely to a polarity of the at least one second permanent magnet. It is further preferred that the second latch release means include a spacer for spacing the at least one first permanent magnet from the at least one second permanent magnet. It is further preferred that the at least one permanent magnet is associated with a movable member that extends through the coil and is operatively connected to the latch bolt so that movement of the at least one permanent magnet move the movable member which moves the latch bolt between the operative and inoperative positions. It is further preferred that the hand engageable member be associated with the movable member so that movement of the hand engageable member moves the movable member to move the latch bolt between the operative and inoperative positions.

It is preferred that the latch bolt be biased towards the operative position. It is further preferred that the latch assembly include spring biasing means for

biasing the latch bolt towards the operative position, however the latch bolt may be biased by the force of gravity acting on the first latch release means.

It is preferred that the activation means renders the electromagnetic means operable for a set period of time, when the authorised signal is read. The set period of time may be any suitable time however it is preferred that the set period of time be 10 seconds.

It is preferred that the latch assembly include visual or audio indication means for indicating an operational condition of any one of the key tag reader, the processing means or the activation means.

It is preferred that the signal read by the key tag reader includes a radio frequency signal (RF), electro magnetic signal or like signal. It is further preferred that the key tag reader includes an antenna for receiving the signal.

It is preferred that the processing means includes a microprocessor and a PCB.

The latch assembly preferably includes a housing for housing at least the latch bolt, the housing having an aperture to receive a strike element when the gate is in the closed position.

The key tag reader may be located in the housing, or alternatively located outside the housing, and in use spaced from the gate.

The housing is preferably located in use in a hollow fence post, and the strike is associated with the gate post.

It will be convenient to hereinafter describe the invention in greater detail by reference to the accompanying drawings showing one example embodiment of a latch assembly according to the invention. The particularity of the drawings and the related detailed description is not to be understood as superseding the generality of the preceding broad description of the invention.

Figure 1 illustrates an isometric view of an example embodiment of the latch assembly installed in a gate post.

Figure 2 is a schematic cross sectional view of the latch assembly with the latch bolt in an operative position.

Figure 3 illustrates the latch assembly from Figure 2 with the latch bolt in the inoperative position.

Figure 4 is a flow chart of the operation of the second latch release means.

Referring firstly to Figure 1 which shows in summary an installed latch assembly having a hand engageable means 2 for operating a first latch release means, and a key tag reader 3 for operating a second latch release means. The latch assembly is attached to a gate post 4 and in particular located within the gate post 4. The gate 5 is shown in a closed position.

Locating the latch assembly within the gate post 4 provides the latch assembly with a level of protection. Protection of the latch assembly 1 can be important particularly where the latch assembly 1 is located in a public area and therefore exposed to vandalism. Furthermore the gate post 4 can be sold with the latch assembly 1 already fitted which reduces installation costs.

Figure 1 shows the hand engageable means 2 being located at a first height whilst the key tag reader 3 is located at a second height which is lower than the first height. It is intended that the latch assembly 1 be installed relative to the gate post 4 such that the first height is accessible by a standing adult whilst the second height is accessible by a seated adult. This enables operation of the latch assembly 1 by not only a standing adult, but also an authorised person at a lesser height such as a shorter adult or person confined to a wheelchair.

While Figure 1 shows the key tag reader 3 located in the gate post, it may alternatively be located at a position transversely spaced from the gate post (not shown). This spaced location of the key tag reader 3 may make it easier for the user to move the gate 5 from the closed position.

The key tag reader 5 of the latch assembly is for reading a key tag (not shown). A key tag for the purposes of this specification includes a device having means to send a signal which may be received by an antenna of the key tag reader. The signal may be a radio frequency signal (RF), electro-magnetic or like signal. The signal may be sent passively by the card or may require user activation. One form of key tag known to the applicant is referred to by those in the electric lock industry in Australia as a proximity card. It should be understood that the term key tag includes but not limited to a proximity card.

The key tag reader 3 shown in Figure 1 is located adjacent to or within an aperture formed in the gate post 5. The aperture enables the key tag reader 5 to freely receive the signal from the key tag without interference that may be caused by the signal attempting to penetrate a metal wall of the gate post 5. This aperture may be plugged by a plastic insert (not shown) so as to protect the key tag reader 5. Another option is to form the gate post 5from a plastics material, in which case the post would not require an aperture.

The operation of the first latch release will now be described with reference to Figures 2 and 3 which illustrates the latch assembly 1 in cross section. Referring initially to Figure 2 which illustrates the hand engageable member being in the form of a pull knob 2 being connected to one end of a movable member 6. The movable member illustrated is in the form of a hollow shaft 6. The connection of the pull knob 2 to the shaft 6 is by way of a screw connection 7 however this is not essential. More specifically the pull knob 2 may be integrally formed with the shaft 6, or alternatively connected by some other means. An end of the shaft 6 remote from the pull knob 2 is operatively connected to a latch bolt 7. The illustration shows an inverted T shaped member 8 directly engaging the latch bolt 7 however this is not essential. More

specifically the shape of the member or the means for engaging the latch bolt 7 may vary.

Referring now to Figure 3 which shows the shaft 6 having been moved in a vertical direction by a user such as a standing adult. This brings flanges of the T shaped member 8 into engagement with the latch bolt 7 to move the latch bolt 7 from an operative position where it engages a tongue 9 of the strike 10 (see Fig. 2), to an inoperative position where it is disengaged from the tongue 9 (see Fig. 3). It will be appreciated that in the inoperative position the tongue 9 can be removed from the latch assembly housing 11 allowing the gate 5 to be moved from a closed position. Once the user releases the pull knob 2 the latch bolt 7 will return to the operative position under the force of gravity and a biasing force created by the spring 22. The spring 22 is clearly not essential as the force required to return the latch bolt could be supplied by gravity alone.

The operation of the second latch release will now be described with reference to Figures 2 and 3. The second latch release means illustrated in figure 2 includes an electro-magnetic means 12 which when operable moves the latch bolt 7 from the operative position. The electro-magnetic means 12 illustrated includes a coil of wire 13, preferably copper wire, coiled on a bobbin. The bobbin is preferably a plastic bobbin. The shaft 6 extends through a bore of the bobbin 14 so as to allow the shaft 6 to move relative to the bobbin 14. The coil of wire 13 is connected to an electrical power source S via an activation means A so that when power is supplied to the coil of wire 13 an electro- magnetic field is created about the bobbin 14 with North at the top of the bobbin 14 and South at the bottom of the bobbin 14.

Figure 2 illustrates two permanent magnets 15,16 located within the shaft 6, the permanent magnets 15,16 being spaced from each other by a spacer 17. Each permanent magnet is oriented such that North is at the top of the magnet and South is at the bottom. When the magnetic field is created the opposite poles of the magnetic field and permanent magnets 15,16 will attract whilst like poles will repel. This will result in movement of the shaft 6 vertically of the latch assembly to move the latch bolt 7 from the operative position. The provision of

two permanent magnets has the advantage over a single permanent magnet as it intensifies the force created and also increases the length of movement of the shaft 6.

It is preferred that the power supplied to the coil of wire 13 be at 12 volt so as to minimise the potential for harm to users. Accordingly where the power source is at 240 volts, it is preferred that the activation means A include a transformer for converting the 240 volts to 12 volts.

The supply of power to the coil of wire is via the activation means A which includes a switch 18. The switch 18 is moved to a closed position as shown in Figure 3 when a processing means P confirms the key tag reader 3 has received an authorised signal. The location of the activation means A and processing means P illustrated in Figures 2 and 3 is not essential and is provided for ease of understanding of the invention only. More specifically the size and location may vary from that shown in Figures 2 and 3. The operation of the activation means A and processing means P will be herewith described with reference to Figure 4.

A flow chart showing the operation of the second latch release means is included as Figure 4. The flow chart illustrates a key tag 19 being brought into proximity of the key tag reader 3 so that a signal sent by the key tag can be received and read by the reader 3. The reader forwards the signal onto a processing means P possibly a microprocessor or PCB for processing the signal. Where the processed signal is revealed to be an unauthorised signal, a visual and or audible indication means I provides an indication to the user, so that the user can appreciate that access has been denied. Where the processed signal has been revealed to be an authorised signal, the visual and or audible indication means I indicates to the user to enable the user to appreciate that access is authorised. The visual indication may be provided by way of a light or LED 20,21 located on the front surface of the reader 3 as shown in Figure 1. The audible indication may be provided by way of a speaker forming part of the processing means. A signal is sent from the processing means 8 to the activation means 4 to close the switch 18 to provide a source of

power to the electro-magnetic means 12. The processing means P and or the activation means A may be programmed so as to provide source of power to the electro-magnetic means for a set period of time. This will enable the second latch release means to hold the latch bolt 7 in an inoperative position for a set period of time. The preferred set period of time is 10 seconds, however this is not essential.

The latch assembly 1 according to the invention has various advantages over the existing latch assemblies. The existing latch assemblies tend to require some manual intervention to retain the latch bolt in an inoperative position, whereas the current invention includes a latch release means capable of holding the latch bolt 7 in the inoperative position. This will assist a user, particularly a mobility impaired user in moving the gate from the closed position. The ability of the key tag reader 3 to be located either within the gate post 4 or at a position spaced from the gate post 4 is a further advantage.

Finally it is to be understood that various other modifications and/or alterations may be made without departing from the spirit of the present invention as outlined herein.