Technical Field

[0001] This invention generally relates to an electromechanical drop bolt assembly for securing a door panel in a closed position relative to a door surround, including a housing for attachment to either the door panel or the door surround. More specifically the electromechanical drop bolt assembly includes a bolt movable relative to the housing between an extended position and a retracted position, and a powered actuator within the housing that is operable to move the bolt between the retracted position and the extended position. The electromechanical drop bolt assembly has a particular application when used with a swing door and it will be convenient to hereinafter describe the invention with reference to this particular application. It should be appreciated however that the invention is not limited to swing door applications only and may find applications with sliding doors as well.

Background of Invention

[0002] Traditionally a drop bolt includes a rod, or flat bar, mountable to an inside surface of a door panel. A user will grasp the rod and slide it relative to the door panel in order to locate a tip of the rod in a recess located in the door surround adjacent the top or bottom edge of the door panel. The drop bolt provides a relatively simple solution for securing the position of a door panel once it is accurately located in a closed position by the user.

[0003] A problem with the traditional the drop bolt is its location on the surface of the door panel allows it to be moved by unauthorised users. One option is to conceal the bolt within the door, or door surround, and to have a powered actuator to move the bolt. This type of electromechanical drop bolt assembly can include a solenoid or motor, for causing rectilinear, or pivoting movement of the bolt relative to the housing. Naturally power is required by the solenoid or motor to operate, and activation of the powered actuator will require a remote access control device, such as a credential reader, adjacent the door. Accordingly cabling for power and communications will be needed to be routed to the housing, either through the door surround or door panel. [0004] When the electromechanical drop bolt assembly is used to control a swing door it can be convenient to mount it in the door surround rather than the door panel, particularly if it is used in a commercial or public environment. Locating the assembly in the door surround reduces its exposure to vandalism such as a blunt force attack on the door panel and allows the cabling to remain in a permanent fixed position.

[0005] While the traditional drop bolt will allow the user to physically align the door in the appropriate position before sliding the bolt into the recess, a problem faced by electromechanical drop bolts is that the bolt is often moved without a user physically touching the door. The door may have come out of alignment with its surround due to a failure with an associated door return mechanism, or in the case of external doors installed in commercial environments a high wind load might be forcing the door out of alignment. The user may be unaware of the misalignment, or unprepared that they may be required to assist in the realignment in order for the powered actuator to move the bolt. It can be only a few millimetres that can prevent the bolt from moving to an extended position and locating in the strike.

[0006] Another problem with electromechanical drop bolts arises when attempting to retract the bolt while the door is pre-loaded by the user leaning on the door or due to a high wind load on the door. This problem is often more apparent to the user when a solenoid is used to retract the bolt, rather than a motor, as often the solenoid struggles to supply sufficient force to overcome the pre-load. However, the actuation of the motor is often too slow to retract the bolt to meet the expectation of the user who is more often used to the speed of actuation of the solenoid.

[0007] The applicant has appreciated that electromechanical drop bolt assemblies could be more broadly desired, if one or more of these issues could be addressed.

[0008] A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was, in Australia, known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims. Summary of Invention

[0009] According to this invention there is provided an electromechanical drop bolt assembly for securing a door panel in a closed position relative to a door surround, including a housing for attachment to either the door panel or the door surround, a bolt movable relative to the housing between an extended position and a retracted position, a powered actuator within the housing that is operable to move the bolt between the retracted position and the extended position, an electronic controller within the housing adapted to receive power supplied from an external power source and control supply of power to the powered actuator, the powered actuator including a drive motor and a drive shaft that is rotated about a drive axis when the motor is operable so as to move the bolt between the retracted position and the extended position, wherein the drive motor and housing are adapted so that the drive motor is fixed in position within the housing at least when the bolt moves from the extended position to the retracted position, a biasing means that urges the bolt towards to the retracted position whereby the bolt is movable to the retracted position without operation of the drive motor.

[0010] The electromechanical drop bolt assembly preferably includes a strike plate separate from the housing for attachment to an other of the door panel or the door surround, the strike plate having a slot adapted for accommodating the bolt when it is in the extended position, the bolt being shaped so that when the bolt is moved from the retracted position to the extended position it can interact with the strike plate to enhance alignment between the strike plate and the housing when the door panel is in the closed position. The bolt may take any suitable shape, and in a preferred arrangement the bolt is shaped to include a ramp section that can slide over the strike plate to enhance said alignment. In a preferred arrangement the ramp section is a truncated cone, so that the bolt can slide over the strike plate on either side of the slot. The applicant has appreciated that providing the bolt with a cylindrical section adjacent the truncated cone section, wherein the cylindrical section has a diameter that is 50% to 70% larger than a diameter of a distal end of the truncated cone section is most preferred. Furthermore, having the truncated cone section has a length that is 50% to 70% of a length of the cylindrical section, is also preferred. The slot in the strike plate may take any suitable shape, and in one preferred arrangement the slot in the strike plate includes a pair of opposed straight sides that converged from a first end of the slot towards a second end of the slot. The pair of opposed straight sides preferably has a width therebetween which is 10% to 20 % greater at the first end than at the second end. It is also preferred that the second end of the slot is substantially semi-circular shaped, particularly where the bolt has a cylindrical section shaped to complement the semi-circular second end of the slot. The housing preferably includes a faceplate having a rectangular shaped aperture through which the bolt can move when adjusting between the retracted position and extended position, it is further preferred that the aperture in the faceplate having a length that is 5% to 10% shorter than a length of the slot in the strike plate. It is further that the electronic controller includes a strike plate sensor for sensing the position of the strike plate relative to the housing, and the electronic controller is adapted to refrain from supplying power to the powered actuator to move the bot towards the extended position until the position of the strike plate relative to the housing is within a tolerance.

[0011] It is preferred that the electronic controller includes a switch that is accessible from outside the housing to adjust a response of the electronic controller to a power failure event of power being failed to be supplied from the external power source to the electronic controller, the switch adjusting the electronic controller between a fail safe response or a fail secure response. It is further preferred that the electronic controller includes an internal power storage adapted to receive power from the external power source, to store that power and supply power to the powered actuator. It is further preferred that the drive shaft is a drive screw, and the powered actuator includes a drive nut that moves along the drive screw when the drive screw is rotated, the drive nut being connected to the bolt so that movement of the drive nut along the drive screw adjusts the position of the bolt relative to the housing. It is further preferred that the electronic controller includes a nut sensor for sensing the position of the nut along the drive axis. It is further preferred that the electromechanical drop bolt assembly include a catch mechanism that is configured to interact with the drive screw so that the drive screw is axially moveable along the drive axis when the catch mechanism is in an inactive condition, and the drive screw is retained in an axial position when the catch mechanism is in an active condition. The catch mechanism preferably includes a catch motor and a catch screw that is rotated about a catch axis by the catch motor when adjusting the catch mechanism between the active condition and the inactive condition. The catch mechanism may include a catch member that moves perpendicularly to the catch axis to engage the powered actuator when the catch mechanism is in the active condition and to disengage from the powered actuator when the catch mechanism is in the inactive condition, however the catch member may move in some other direction to engage with the powered actuator. It is preferred that the electronic controller includes a catch sensor for sensing the condition of the catch mechanism. It is further preferred that the catch mechanism includes a catch nut that moves along the catch screw when the catch screw is rotated, the catch sensor monitoring the position of the catch nut along the catch axis. The electromechanical drop bolt assembly preferably includes a slide member on which the drive screw is mounted, wherein the slide member is axially movable towards a first position under the influence of the biasing means, and axially moveable in an opposite direction towards a second position on operation of the drive motor. It is further preferred that the electronic controller includes a slide member sensor for sensing the position of the slide member when in the first position and the second position. It is further preferred that the catch mechanism is adapted so that the catch member engages the slide member when the slide member is in the second position and the catch mechanism is in the active condition so as to retain the slide member in the second position. It is further preferred that the electronic controller is adapted to supply power to the drive motor to cause the drive screw to rotate in a first direction and a second direction opposite to the first direction so as to cause the bolt to move towards the extended position and the retracted position respectively when the slide member is retained in the second position. It is further preferred that the electronic controller is adapted to respond to a pre-load event for when load applied to the door inhibits the bolt from moving from the extended position under the influence of the biasing means, the electronic controller is adapted to sense that the slide member has not moved from the second position after the catch member has disengaged from the slide member and will supply power to the drive motor to rotates the drive screw in the second direction so as to initiate movement of the bolt from the extended position until the slide member can move from the second position towards the first position under the influence of the biasing means. [0012] An electromechanical drop bolt preferably includes a transmission acting between the drive motor and the drive screw, the transmission being configured to permit transmission of torque from the drive motor to the drive screw while allowing for axial movement of the drive screw relative to the drive motor when the slide member moves between the first position and the second position, so that the drive motor can remain in said fixed position within the housing. This arrangement allows for the wires connecting the drive motor with the electronic controller to remain stationary, avoiding wire bend fatigue and break up due to the motor moving within the housing.

[0013] The bolt may move in any manner between the extended position and the retracted position, and it is preferred that the bolt is mounted within the housing so as to pivot about a bolt axis between the extended position and the retracted position. The bolt may, alternatively move linearly. The bolt preferably includes a linkage that is configured to connect with the powered actuator so that end pressure when applied to the bolt when the bolt is in the extended position creates a force that is directed substantially perpendicularly to the drive axis.

[0014] The electronic controller may include a visual indicator for indicating operation of the powered actuator. The preferred form is an LED that can flash or remain solid, over a range of colours to indicate a range of status such as locked, unlocked and unlocking.

[0015] An electromechanical drop bolt may include a shroud within the housing positioned adjacent the bolt defining a void that accommodates the bolt when the bolt is in a retracted position. The function of the shroud is to impede the ingress of dirt into the housing that would otherwise adversely impact on the inner function of the electromechanical drop bolt. It is further preferred to include an elastomer member positioned between the shroud and a front of the housing for impeding ingress of liquid that might be in the void further into the housing. It is still further preferred that the bolt includes a linkage to connect with the powered actuator, the shroud having a pathway for the linkage to pass by or through the shroud to the powered actuator, whereby the linkage can be shaped to interact with the shroud when the bolt is in the extended position for impeding ingress of liquid that might be in the void further into the housing through the pathway. The electromechanical drop bolt assembly preferably includes a barrier that is movable within the housing relative to a closed position for impeding ingress of liquid that might be in the void further into the housing through the pathway. The barrier is preferably adapted to move between a closed position and an open position, and the barrier is adapted to interact with the bolt so that said open position for the barrier corresponds with the bolt being in the extended position. It is further preferred that the barrier is adapted to adjust between the closed position and the open position on operation of the powered actuator.

Brief Description of Drawings

[0016] The invention will now be described in further detail by reference to the accompanying drawings. It is to be understood that the particularity of the drawings does not supersede the generality of the preceding description of the invention.

[0017] FIG. 1 is an isometric view of an electromechanical drop bolt assembly according to the invention illustrated schematically installed in a door surround adjacent a door panel.

[0018] FIG. 2 is a side elevation view of the electromechanical drop bolt assembly from FIG. 1.

[0019] FIG. 3 is an isometric view of the electromechanical drop bolt assembly from FIG. 1 from a bottom end of the housing, with a lid removed.

[0020] FIG. 3A is a detailed view of the electromechanical drop bolt assembly from detail A of FIG. 3.

[0021] FIG. 4 is an exploded isometric view of the electromechanical drop bolt assembly from FIG. 1.

[0022] FIG. 4A is a reverse perspective view of detail A of FIG. 4.

[0023] FIG. 5 is a side elevation view of the electromechanical drop bolt assembly showing the bolt in a retracted position and the slide member in a second position.

[0024] FIG. 5A is a detailed view of A from FIG. 5. [0025] FIG. 6 is a reverse side view of the electromechanical drop bolt assembly from FIG 5.

[0026] FIG. 6A is a detailed view of A from FIG. 6.

[0027] FIG. 7 is a side elevation view of the electromechanical drop bolt assembly with the bolt in the extended position with the slide member in the second position.

[0028] FIG. 7A is a detailed view of A from FIG. 7.

[0029] FIG. 8 is a reverse side view of the electromechanical drop bolt assembly from FIG. 7, however showing the catch mechanism in an inactive condition.

[0030] FIG. 8A is a detailed view of A from FIG. 8.

[0031] FIG. 9 is a side elevation view of the electromechanical drop bolt assembly with the bolt in the retracted position and the slide member in the first position.

[0032] FIG. 9A is a detailed view of A from FIG. 9.

[0033] FIG. 10 is a front elevation view of the electromechanical drop bolt assembly with the bolt in a retracted position and the strike plate out of alignment but within intolerance with the faceplate.

[0034] FIG. 11 is a front elevation view of the electromechanical drop bolt assembly with the bolt in the extended position and the strike plate in alignment with the faceplate.

Detailed Description

[0035] FIG. 1 illustrates the isometric view of an electromechanical drop bolt assembly 1 shown in dashed line, with a door panel 2 and a door surround 3 both illustrated schematically. It can be appreciated from FIG. 2 that the electromechanical drop bolt assembly 1 includes a housing 4 and a strike plate 5, with the housing 4 mounted in the door surround 3 and the strike plate 5 mounted to the door panel 2. Both the housing 4 and the strike plate 5 are fastened to their respective door surround 3 and door panel 2 by a series of screws 6. [0036] It should also be noted that FIG. 1 (and more clearly in FIG 2) illustrates a bolt 7 of the electromechanical drop bolt assembly 1 in an extended position, and that the door panel 2 is formed with a cavity 8 to accommodate the bolt 7 when in the extended position. FIGS. 1 and 2 also illustrate the door surround 3 being formed with a cavity 9 to accommodate the housing 4 when installed. It should also be appreciated from FIG. 1 that the door surround 3 includes a conduit 10 to allow cabling (not shown) therethrough for connecting the electromechanical drop bolt assembly 1 to an external power source (not shown) and an remote access control device (not shown). The access control device may take any suitable form, and could include a credential reader or touch pad positioned adjacent the door surround 3, or a manually monitored control located remote from the door surround 3.

[0037] FIG. 3, and FIG. 3A in particular, illustrate a bottom end of the housing 4 including an input socket 11 for connecting to the cables from the external power source and the communication cables for the access control device. FIG. 3A also illustrates a micro USB connector 12 for connecting the electromechanical drop bolt assembly 1 to a local diagnostic device (not shown) for facilitating local diagnostic and maintenance on the electromechanical drop bolt assembly. The type of maintenance envisaged by the applicant includes firmware upgrades or the like. The USB connection could also be used in facilitating in the initial set-up of the electromechanical drop bolt assembly 1. FIG. 3A also illustrates a switch for adjusting the manner in which the electromechanical drop bolt assembly 1 responds to a power failure event. The function of the switch 13 will be described in greater detail later in the specification, however it ought to be appreciated from FIG. 3A that the switch 13 is accessible from outside the housing 4.

[0038] Referring now to FIG. 4, and it ought to be appreciated that the housing 4 is formed from the combination of a base 14, a lid 15 and a faceplate 16. It should also be noted that the image of the housing 4 shown in FIG 3 was of the housing 4 with the lid 15 removed from the base 14. In general terms FIG. 4 illustrates an electronic controller 17, a catch mechanism 18, a powered actuator 19, the bolt 7, and a shroud 20, that all locate within the base 14. FIG. 4 also illustrates the strike plate 5 positioned spaced from the faceplate 16. [0039] The base 14 includes a shaft 21 and the shroud 20 has an aperture 22 through which the shaft 21 extends when the shroud 20 is positioned in the base 14. The bolt 7 includes a pivot 23 having a cylindrical bore 24 formed therethrough so as to locate the pivot 23 on the shaft 21. Furthermore, the surround of the aperture 22 forms a boss over which the pivot 23 can rotate when the bolt 7 moves between he extended position as illustrated in FIG. 2 to a retracted position as illustrated in FIG. 9.

[0040] The shroud 20 is attached to the faceplate 16 by a pair of screws (not shown) which extend through circular apertures 25 positioned each side of a rectangular shaped aperture 26 and into the shroud 20. The function of the shroud 20 is to limit the ingress of dirt that may enter the housing 4 through the rectangular aperture 26 from travelling further into the housing 7, and potentially fouling the operation of the powered actuator 19, the catch mechanism 18 and the electronic controller 17. The shroud 20 may be made from any suitable material, and any material suitable for facilitating a tight seal between the shroud 20 and the faceplate 16 to limit the ingress of dirt. Alternatively, or in combination therewith, an elastomeric grommet 71 could be provided between the shroud 20 and the faceplate 16. The gromet 71 would facilitate such a seal, and also limit the ingress of liquid that might slide between the shroud 20 and the faceplate 16 towards the electronic controller 17, particularly when the housing 4 is installed in a vertical orientation.

[0041] It ought to be appreciated from FIG. 4 that the bolt 7 includes an arm 27 extending out from the pivot 23 on which a head 28 is attached by way of a screw fastener 29. Whilst the head 28 could be integrally formed with the arm 27, attaching the head 28 in this manner allows to pivot about the arm 27 when the head 28 engages the strike plate 5 whilst moving from a retracted position to an extended position. The head 28 includes a cylindrical section 30 and a truncated cone section 31. The truncated cone section 31 functions as a ramp when to interact with a slot 32 in the strike plate 5, in a manner that will be described later in the specification.

[0042] Referring still to FIG. 4 which illustrates the bolt 7 having a linkage member 33 which provides a link between the powered actuator 19 with the bolt 7. More specifically the linkage member 33 includes a slot 34 formed therein which engages the powered actuator 19. The linkage member 33 is also shaped to interact with the shroud 20 to limit the ingress of dirt further into the housing, particularly when the bot 7 is in the extended position (see figure 7).

[0043] The preferred embodiment of the powered actuator 19 illustrated in FIG. 4 includes a drive motor 35, a transmission 36, a drive screw 37, a drive nut 38 and a slide member 39. A bracket 40 is provided to fix the position of the drive motor 35 within the base 14. The drive motor 35 is connected to the transmission 36 which includes an input member 41 and an output member 42 both of which are rotatable about a drive axis X-X. The output 42 of the transmission 36 is connected to the drive screw 37 on which is located the drive nut 38. The output 42, drive screw 37 and drive nut 38 are all captured by the slide member so as to move together along the drive axis X-X. A cap 43 which fits over the output 42 and attaches to the slide member 39 to also move therewith. A compression spring 44 is located within the base 14 fitting over a shaft 45. An opposite end of the spring 44 locates within a socket (obscured) in the slide member 39 so as to bias the slide member 39 towards the drive motor 35.

[0044] The drive nut 38 includes a threaded bore which engages the drive screw 37. The drive nut 38 includes a post 46 that locates in the slot 34 of the linkage member 33, so that the post 46 can slide within the slot 34. The interaction of the drive nut 38 with the linkage member 33 will be described later in the specification.

[0045] FIG. 4 illustrates a drive nut extension 47 which can be attached to the drive nut 38, or alternatively (not shown), the drive nut extension 47 could be integrally formed with the drive nut 38. The drive nut extension 47 includes a barrier 48 that interacts with the shroud 20 when the bolt 7 is in the retracted position (see figure 5). When the barrier 48 is in this position it limits the ingress of dirt into the housing 4 between the linkage member 33 and the shroud 20.

[0046] The drive nut extension 47 includes a blocker 50 that interacts with nut sensors 51 A, 51 B on the electronic controller 17 (see FIG. 4A). The cap 43 of the slide member 39 also includes a blocker 52 which is adapted to interact with a slide member sensor 53 on the electronic controller 17 (see FIG. 4A). These interactions will be described in greater detail later in the specification. [0047] The catch mechanism 18 illustrated in FIG. 4 includes a catch motor 54 that is supplied power from the electronic controller 17. The catch motor 54 is attached to the base 14 by way of a bracket 55 so that the catch motor 54 is fixed relative to the base 14. The catch motor 54 rotates a catch screw 56 which is engaged by a catch nut 57 so as to move along a catch axis Y-Y on rotation of the catch screw 56 about the catch axis Y-Y. The catch nut 57 has an integrally formed extension 58 which includes a blocker 59 thereon for interaction with catch sensors 60A and 60B (see FIG. 4A on the electronic controller 17). The catch nut extension 58 is formed with an aperture 61 therein to receive a pin 62. The catch mechanism 18 also includes a catch member 63 which is formed with a slot 64 within which the pin 62 can slide there along. The catch member 63 is movable in a direction substantially perpendicular to the catch axis Y-Y in a manner that will be described later in the specification, however, it should be noted in FIG. 4 that the slide member 39 is formed with a recess 65 adjacent one end at its side to accommodate the catch member 63 when the catch mechanism 18 is in an active condition.

[0048] FIG. 4 illustrates the electronic controller 17 also including a strike plate sensor 66 which is adapted to interact with a magnet 67 in the strike plate 5 so as to indicate the relative alignment between the strike plate 5 in the housing 4 when the electromechanical drop bolt assembly 1 is in use. FIG. 4 also indicates the electronic controller includes an indicator LED 68 that is visible through a lens 69 positioned in the faceplate 16. The indicator LED 68 functions to provide a visual indicator to the user of various functions of the electromechanical drop bolt assembly 1. The LED could, for example emit a solid red light when lock, a red flashing light when in the process of locking, a solid green light when unlocked and a flashing green light when unlocking. Clearly other combinations of colours and flashing sequences are possible.

[0049] FIG. 4A illustrates the electronic controller 17 as including an internal power storage 70 which is adapted to receive power from the external power supply, to store that power and to supply power to the powered actuator 19 when authorised credentials have been presented to the access control device. The internal power storage 70 may take any suitable form, and the preferred form is a super capacitor as it can efficiently supply a short burst of power to the dive motor 35 or catch motor 54 and slowly recharge. In a power failure event of power failing to be supplied to the electronic controller 17 from the remote power source, the internal power storage 70 will still have power to allow the electronic controller to adopt a fail safe or fail secure response (also referred to as power to lock and power to open). This response can be selected by the installer setting the switch 13 before installing the hosing 4 in the cavity 9. Whilst wiring is not illustrated, it is to be understood that a wiring loom is provided to connect both the drive motor 35 and the catch motor 54 to the electronic controller 17. It should be appreciated that with the drive motor 35, catch motor 54 and the electronic controller 17 all fixed in position within the housing 4, the wiring loom will not move during the operation of either of the drive motor 35 or the catch motor 54. This minimises any wire fatigue that might be experienced by a wiring loom that must move with each movement of the bolt.

[0050] The operation of the electromechanical drop bolt assembly 1 will now be described with reference to figures 5 to 9. Referring now to FIG. 5 which illustrates the bolt 7 in the retracted position, and the slide member 39 in a second position. It can be appreciated from FIG. 5A that the blocker 50 is interacting with nut sensor 51a to indicate the position of the drive nut 38 to the electronic controller 17. Furthermore, the blocker 52 is interacting with the slide member sensor 53 to indicate to the electronic controller 17 that the slide member 39 is in the second position. FIG. 6 illustrates the reverse side view showing the catch mechanism 18 in the active condition whereby the catch member 63 is located in the recess 65 formed in the slide member 39 so as to prevent movement of the slide member 39 towards the motor 35. It can be appreciated from FIG. 6A that the blocker 59 is interacting with the catch sensor 60A to indicate the catch mechanism 18 is in the active condition.

[0051] FIG. 7 illustrates the bolt 7 having been pivoted to the extended position as a result of a user supplying credentials to the access control device with instructions to move the bolt 7 to the extended position. This is achieved by the slide member 39 being retained in the second position by the catch member 63 locating in the recess 65 (see FIG 6) whilst the drive motor 35 rotates the transmission 36 to rotate the drive screw 37 in a first direction. Rotation of the drive screw 37 in the first direction causes movement of the drive nut 38 along the drive axis X-X, and through interaction between the linkage member 33 and the drive nut 38, causes pivoting of the bolt 7 to the extended position. It can be appreciated from FIG. 7A that the blocker 50 is now interacting with nut sensor 51 B. Once the blocker 50 reaches nut sensor 51 B the electronic controller ceases supplying power to the drive motor 35. It should also be noted in FIG 7 A that the blocker 59 is still interacting with the catch sensor 60A, indicating the catch mechanism 18 is in the active condition.

[0052] FIG. 8 illustrates the catch mechanism 18 in the instant that it has been adjusted to the inactive condition whereby the catch member 63 is retracted from the recess 65 in the slide. This is achieved by a user supplying access credentials to the access control device with instructions to move the bolt 7 to the retracted position. The electronic controller 17 supplies power to the catch motor 54 casing the catch nut 57 to move along the catch axis Y-Y. Furthermore, FIG. 8A illustrates the blocker 59 having been moved to interact with the catch sensor 60B, at which time the electronic controller 17 ceases supplying power to the catch motor 54. The catch mechanism 18 is now considered in the inactive condition.

[0053] Once the catch mechanism 18 is in an inactive condition FIG. 9 illustrates the bolt 7 moved to a retracted position as a result of movement of the slide member 39 to a first position. This is achieved by disengagement of the catch member 63 from the recess 65 in the slide member (see figure 8) allowing for the spring 44 to move the slide member 39 to the first position. The use of the spring achieves a swift movement of the bolt 7 from the extended position to the retracted position which is desirable for users. It can be appreciated from FIG. 9A that the blocker 50 is again interacting with nut sensor 51a to indicate that the bolt 7 is in the retracted position.

[0054] In order to return the slide member 39 to the second position, as illustrated in figure 5, the drive motor 35 rotates the drive screw 37 in a second direction opposite to the first direction. The drive nut 38 remains stationary while the drive screw 37 is drawn through the threaded bore therein, drawing the slide member 39 back to the second position and lengthening the transmission 36. This movement of the slide member also compresses the spring 44. Thereafter the catch motor 54 operates to move the catch member 63 into the recess 65 in the slide member 39 to retain it in the second position.

[0055] It ought to be appreciated that the electronic controller 17 will monitor power supplied from the external power source, and in the power failure event will use the internal power storage 70 to supply power to either of the catch motor 54 or the drive motor 35, to adjust the position of the bolt 7 depending upon the setting of the fail safe/fail secure switch.

[0056] Referring now to FIG. 10 which illustrates the bolt 7 in a retracted position with the strike plate 5 slightly out of alignment with the housing 4. It can be appreciated that the slot 32 in the strike plate 5 includes a pair of opposed straight sides that converge from a first end of the slot 32 towards a second end of the slot 32 and terminate in a semi-circular shape second end. The converging sides of the slot 32 in combination with the conical section 37 of the head 28 acts as a ramp function to realign the strike plate 5 with the housing 4 when the bolt 7 moves from the retracted position to the extended position as shown in FIG 11. Flowever, if the strike plate sensor 66 (see FIG 4) senses the magnet 67 is too far out of alignment, the electronic controller 17 will not supply power to the drive motor 35. This prevents the bolt 7 crashing into the strike plate 5 if it is too far out of alignment.

[0057] It ought to be appreciated from the foregoing that the combination of a spring to retract the bolt 7 and a drive motor 35 provides a functional and reliable electromechanical drop bolt assembly.

[0058] While the invention has been described in conjunction with a limited number of embodiments, it will be appreciated by those skilled in the art that many alternative, modifications and variations in light of the foregoing description are possible. Accordingly, the present invention is intended to embrace all such alternative, modifications and variations as may fall within the spirit and scope of the invention as disclosed.

[0059] The present application may be used as a basis or priority in respect of one or more future applications and the claims of any such future application may be directed to any one feature or combination of features that are described in the present application. Any such future application may include one or more of the following claims, which are given by way of example and are non-limiting in regard to what may be claimed in any future application.