AU2016301111B2

AU2016301111B2 - Electric strike system with keeper monitoring

Info

Publication number: AU2016301111B2
Application number: AU2016301111A
Authority: AU
Inventors: Stefan BOTHA
Original assignee: Assa Abloy Australia Pty Ltd
Current assignee: Assa Abloy Australia Pty Ltd
Priority date: 2015-07-30
Filing date: 2016-07-28
Publication date: 2021-08-19
Anticipated expiration: 2036-07-28
Also published as: CN107923196A; GB201802964D0; CN107923196B; AU2016301111A1; KR20180034648A; WO2017015718A1; DE112016003432T5; GB2556790B; NZ739558A; GB2556790A

Abstract

This invention relates to an electric strike system (1) for use with a latch assembly (3) which monitors a position of a keeper (6) relative to a housing (8). More specifically, the electric strike system (1) includes a powered actuator (16) which moves a detent (22) relative to the housing (8) between a locked and released condition. A keeper sensor (31) is included to sense the position of the keeper (6) relative to the housing (8) so as to prevent supplying power to the powered actuator (16) when the keeper (6) is in the open position.

Description

ELECTRIC STRIKE SYSTEM WITH KEEPER MONITORING

[0001 ] This invention relates to an electric strike system for use with a door latch assembly. More specifically the electric strike provides for monitoring of the keeper.

[0002] An electric strike includes a strike or keeper that is movable relative to a housing. The housing is normally mounted in a door frame, and the electric strike is operable for releasably retaining a latch bolt assembly installed on the door mounted to the frame. When the electric strike is in a locked condition the door is prevented from moving from the closed condition, and when in the unlocked condition the door is movable from the closed position without operating the latch bolt assembly. Generally the electric strike is programmed with a specific time delay of say five seconds before returning to the locked condition, so as to allow the door to return to the closed position. It can be problematic if the door takes longer than the specified time to return to the closed position.

[0003] The electric strike may be connected to some form of electronic security reader mounted proximate the door frame so as to limit access through the door to only those people carrying appropriate security swipe tags or cards. The use of a swipe tag in combination with an electric strike is an attractive egress security option for relatively high traffic areas such as commercial office buildings, multi dwelling accommodation and public buildings such as libraries and hospitals. The use of the electric strike in a public environment however will expose it to a ranger of users. One problem that the applicant is aware of is when the keeper is held in an open condition for an extended period of time, and the issues that this can cause with the electric strike trying to return to the locked condition. Depending upon the locking mechanism within the electric strike this can cause problems ranging from damage to the locking mechanism, through to the keeper being "locked" in an open condition.

[0004] An electric strike includes a powered actuator that requires power for adjusting the condition between locked and unlocked. One form of powered actuator is a solenoid which has a plunger that moves relative to a housing in response to power being supplied, and generally with a spring to return the plunger to its original position without power. Another form of powered actuator is a motor that rotates a drive shaft, which requires power to both lock and unlock the electric strike. One advantage that the spring in the solenoid provides is in a power failure event the plunger can still return to its original position. Accordingly the solenoid can be arranged so that in a power failure event the electric strike operates in a fail-safe mode or a fail secure mode which corresponds to the electric strike adopting an unlocked and locked condition respectively.

[0005] 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.

[0006] According to this invention there is provided an electric strike system for use with a door latch assembly including an electric strike assembly including a housing, a keeper that is movable relative to the housing between an open position and a closed position with a biasing means urging the keeper towards the closed position, a detent that is movable relative to the housing between a locked condition and a released condition, a powered actuator that when powered adjusts the condition of the detent, a keeper sensor which senses the position of the keeper, and a controller which controls supply of power to the powered actuator and monitors signals received from the keeper sensor so as to prevent supplying power to the powered actuator while the keeper is in the open position.

[0007] The electric strike system preferably includes a power storage device within the housing for providing power at least to the controller. This provides the advantage of an independent power source to power the controller, particularly in a power failure event. The power storage device may take any form however its preferred form is super capacitor, as this allows for a relatively quick discharge and recharge over numerous cycles. Alternatively the power storage device may take the form of a rechargeable battery. [0008] The controller is preferably mounted within the housing, however it may be installed elsewhere within the electric strike system. This could include mounting the controller in the security reader mounted proximate the door frame. Where the controller is mounted within the housing, and the electric strike system preferably includes electric terminals for connecting the controller to a main power source external to the housing. Where the controller includes a Printed Circuit Board (PCB) the terminals may include wires with a plug for a socket arrangement to plug into mains power. It is further preferred that the power storage device is mounted on the controller as this simplifies the assembly of the electric strike, however the power storage device may be located elsewhere within the housing.

[0009] It is preferred that the electric strike system be capable of accommodating a power failure event, and in particular the controller be operable in a fail-safe mode whereby in the event of the power failure event the power storage device provides power to the controller so as to adjust the condition of the detent to the release condition, or in a fail secure mode whereby in the event of the power failure event the power storage device provides power to the controller so as to adjust the condition of the detent to the locked condition provided the keeper is in the closed position. It is preferred the adjustment between fail safe and fail secure is relatively simple and may include a switch which is adjustable from outside the housing for adjusting operation of the controller between the fail-safe mode and the fail-secure mode. The switch may be operable at a front face of the housing, as this provides the advantage of the operation of the controller being adjustable when the electric strike is mounted.

[0010] The keeper sensor may take any suitable form and one form includes a hall sensor while the keeper includes a magnet which is sensed by the hall sensor when the keeper is in the closed position. This provides the advantage of the sensor sensing the position of the keeper without requiring physical contact. Another alternative is for the sensor to take the form of a reed switch which would interact with the magnet on the keeper, or a micro switch which may physically interact with the keeper itself. It is preferred that the keeper sensor is mounted to the controller, as this simplifies the assembly process of the electric strike. Alternatively the sensor may be located elsewhere in the housing.

[001 1 ] The electric strike system may include a detent sensor that senses the condition of the detent, and the controller monitors signals received from the detent sensor. Whilst the controller may alternatively include a memory function to remember where the detent should be on the basis of previous instructions, it is preferred that sensors be included to actually sense the position of the detent relative to the keeper. The detent sensor may take any form and one form may include one, or a pair, of hall sensors and the keeper includes a magnet which is sensed by the either hall sensor when the detent is in either locked condition or the released condition. This provides the advantage of the sensor sensing the position of the detent without requiring physical contact. Another alternative is for the sensor to take the form of a reed switch which would interact with the magnet on the detent, or a micro switch which may physically interact with the detent itself. It is preferred that the detent sensor is mounted to the controller, as this simplifies the assembly process of the electric strike. Alternatively the sensor may be located elsewhere in the housing.

[0012] The powered actuator may take any form however it is preferred that it includes an electric motor and a drive shaft that rotates about an actuation axis when energised. The use of an electric motor has the advantage over a solenoid as it can be capable of producing reasonably high torque. The controller is preferably adjustable in supplying power to the electric motor so as to adjust between operating in a forward mode and a reverse mode so as to rotate the drive shaft in a clockwise and anti-clockwise direction. The detent includes a threaded bore and drive shaft includes a threaded portion that is located within the threaded bore of the detent. The threaded bore of the detent and the threaded portion of the drive shaft interact so that rotation of the shaft causes movement of the detent in the direction of the actuation axis.

[0013] It is further preferred that an electric strike system according to any one of the preceding claims including a security reader for reading a swipe tag.

[0014] It will be convenient to hereinafter describe preferred embodiments of the invention with reference to the accompanying drawings. The particularity of the drawings is to be understood as not limiting on the preceding broad description of the invention.

[0015] Figure 1 is a cross-sectional view of an installed electric strike system including an electric strike assembly with a security reader in a diagrammatic form.

[0016] Figure 2 is an isometric view of a preferred embodiment of the electric strike assembly with a keeper in the closed position.

[0017] Figure 3 is an isometric view of a strike assembly from Figure 2 with the keeper in the open position.

[0018] Figure 4 is an isometric view of a preferred embodiment of the electric strike assembly in an exploded form, with a rear cover of the housing removed.

[0019] Figure 5 is an isometric view of a preferred embodiment of the electric strike assembly with the rear cover removed to reveal the keeper in a closed position and the detent in a release condition.

[0020] Figure 6 is an isometric view of the electric strike from Figure 5 with the detent in a locked condition.

[0021 ] Figure 7 is a partial isometric view with the keeper in a closed position and the detent in a release condition.

[0022] Figure 8 is an isometric view of the electric strike assembly from Figure 7 with the keeper moved to the open position.

[0023] Figure 9 is an isometric view of the electric strike assembly from Figure 7 with the detent adjusted to the locked condition.

[0024] Figure 1 shows, in very diagrammatic form an electric strike assembly 1 mounted to an edge of a door frame 2. A latch assembly 3 including a latch bolt 4 is illustrated as mounted to an edge on an adjacent door 5. The electric strike assembly includes a keeper 6 which is shown in Figure 1 in a closed position. When the keeper 6 is held in the closed position it retains the bolt 4 and therefore retains the door 5 from being removed relative to the door frame 2. A handle (not shown) may be included at least on the outside of the door 5 to facilitate moving the door 5 relative to the frame 2. It ought to be noted however that the handle is not operably connected to the latch bolt 4 to cause any movement thereof. More specifically whilst the bolt 4 can be moved to the retracted position while the door 5 is being returned to the closed position, the latch bolt 4 returns to the extended position as shown by operation of a spring 7. Figure 1 also illustrates electric terminals connecting the electric strike assembly 1 to a power source V, and a security reader 38 connected to the electric strike assembly 1 for reading swipe tags (not shown) or the like. In a preferred embodiment the electric strike system includes the combination of the electric strike assembly (1 ), electric terminals and a security reader (38).

[0025] Referring now to Figure 2 which illustrates the electric strike assembly 1 having a housing 8. The housing 8 is provided with apertures 9 on the face 10 of the housing 8 to enable the housing 8 to be attached to the door frame 2 (see Figure 1 ) by fasteners such as screws (not shown). The keeper 6 is mounted to the housing 8 for movement relative thereto. Figure 3 illustrates the keeper 6 having being moved from the closed position shown in Figure 2. This is achieved by a user opening the door 5 so as to pivot the keeper 6 relative to the housing 8. The keeper 6 is returned to the closed position by the urging of a spring 1 1 located around a pivot axis of the keeper 6 (see Figure 3).

[0026] Figure 4 illustrates the electric strike 1 in an exploded view with a rear cover 12 removed from a base 13 of the housing 8. The base 13 illustrated includes a pair of spaced mounts 14, 15 formed therewith on which the keeper 6 is mounted. The mounting arrangement is one that permits the keeper 6 to pivot relative to the base 13 as was explained with reference to Figures 2 and 3.

[0027] The electric strike 1 according to the invention includes a powered actuator 16 which may take any form. Figure 4 illustrates one preferred form of powered actuator 16 including an electric motor 17 and a drive shaft 18. The electric motor 17 includes a housing 19 with an output spindle 20 that is rotatable about an actuation axis X-X upon power being supplied to the electric motor 17. The motor 17 may take any form however a preferred form is a 12 volt motor. The output spindle 20 is preferably shaped so as to interact with a proximal end 21 of the drive shaft 18. Figure 4 illustrates the proximal end 21 of the drive shaft 18 being flared and includes a bore (not shown) which is shaped to complement the external surface of the output spindle 20 so as to provide a driving connection between the output spindle 20 and the proximal end 21 of the drive shaft 18. It is preferred that the actuator 16 be capable of operating in a forward mode and a reverse mode so as to rotate the drive shaft 18 in a clockwise and anti-clockwise direction respectively. This may be achieved by any suitable arrangement, and the preferred arrangement illustrated involves utilising a motor 17 that allows for reverse polarity of the power supplied thereto so as to adjust rotation of the output spindle 20 between clockwise and anticlockwise. An alternate, not illustrated, may include a gearbox acting between the output spindle 20 of the electric motor 17 and the drive shaft 18 so as to permit adjustment between rotating the drive shaft 18 in a clockwise and anticlockwise direction.

[0028] The electric strike 1 according to the invention includes a detent 22 that is movable relative to the housing 8 between a lock condition and a release condition. The detent 22 illustrated is a unitary member having a driven portion 23 formed with a threaded bore 24. The threaded bore interacts with a threaded portion 25of the drive shaft 18 so that rotation of the drive shaft 18 in the clockwise or anti-clockwise direction results in movement of the detent 22 relative to the housing 8. The detent also includes an abutment 26 which interacts with an arm 27 of the keeper 6 in a manner that will be described in greater detail with reference to Figures 7 to 9. The detent 22 is also formed with a slot 28 between the abutment 26 and driven portion 23 which can accommodate the arm 27 of the keeper 6 when the detent 22 is in the release condition. The interaction of the slot 28 with the arm 27 of the keeper 6 will be described in greater detail with reference to Figures 7 to 9.

[0029] The electric strike 1 according to the invention also includes a controller 29 which is illustrated in Figure 4 mounted within the housing 8 to control supply of power to the powered actuator 16. The controller 29 may be located elsewhere, including for example the security reader 38 (see Figure 1 ). Figure 4 illustrates a preferred embodiment of the controller 2 in the form including a printed circuit board 30 (PCB) which is connected by wires (not shown) to the electric motor 17 when the electric strike 1 1 is assembled. The PCB 30 includes electronic circuitry (not shown) in order to control a supply of power.

[0030] The electric strike 1 according to the invention also includes a keeper sensor 31 which senses the position of the keeper 6. A preferred form of keeper sensor 31 illustrated in Figure 4 is in the form of a hall sensor mounted to the PCB 30 which sensors a magnetic field produced by a magnet 32 located in the arm 27 of the keeper 6. This interaction will be described in greater detail with reference to Figures 7 to 9.

[0031 ] It is a preferred aspect of the invention that the electric strike include a detent sensor 33, 34 for sensing the condition of the detent 22. Figure 4 illustrates a pair of hall sensors 32, 34 mounted to the PCB 30 which monitor a magnetic signal produced by a magnet 35 mounted to the detent 22.

[0032] It ought to be appreciated that the location of the magnets 32, 35 on the keeper 6 and detent 22, along with the location of the hall sensors 31 , 33, 34 on the PCB 30 may vary from that as illustrated in Figure 4. Furthermore the invention is not limited to sensors 31 , 33, 34 in the form of hall sensors only, and instead read switches or micro switches may be used.

[0033] It is a preferred aspect of the invention that the electric strike 1 include electric terminals in the form of wires (not shown) for wiring the controller 29 to a mains power source. It is also preferred that the electric strike 1 include a power storage device 36 within the housing 8 for providing power to the controller 29. The preferred form of power storage device 36 is a super capacitor and it is further preferred that the super capacitor be mounted on the PCB 30 providing backup power for the controller 29 in a power failure event from the mains power source.

[0034] It ought to be appreciated that any power storage device 36, including a super capacitor, will have limited power to supply to the controller 29 in a power failure event from the mains power source. Accordingly it is preferred that the controller 29 be adjustable to operate in either a failsafe mode or fail secure mode in a power failure event from the mains power source. The adjustment may be achieved by any suitable arrangement and in the embodiment illustrated includes a switch 37 (see Figure 2) which is adjustable from outside the housing 8 for adjusting operation of the controller 29. The switch 37 may be located anywhere on the housing 8, including at the front face 10 of the housing 8 to permit adjustment of the controller 29 whilst the electric strike 1 is installed. The switch 37 may be covered as illustrated in Figure 2 to avoid tampering. When the controller 29 is operating in a failsafe mode, in the event of a power failure event, the power storage device 36 provides power to the controller 29 so as to adjust the condition of the detent 22 to the release condition. In contrast when operating in a fail secure mode, in the event of the power failure event the power storage device 36 provides power to the controller 29 to adjust the condition of the detent 22 to the lock condition, provided the keeper 6 is in the closed position.

[0035] The controller 29 of the electric strike 1 is programmed to monitor signals received from the keeper sensor 31 so as to prevent supplying power to the powered actuator 16 while the keeper 6 is in the open position. Referring firstly to Figure 5 which illustrates detent 22 in the release condition and the keeper 6 in the closed position. Keeper sensor 31 is monitoring the magnet in the keeper arm 27 and sending a signal to the controller 29 to indicate the keeper is in the closed position. Whilst the keeper 6 remains in the closed position the controller 29 can supply power either from the mains power source or from power storage device 36 (see Figure 4) to the electric motor 17 so as to rotate the drive shaft 18. Rotation of the drive shaft 18 will cause the detent 22 to move from the released condition illustrated in Figure 5 to a locked condition as illustrated in Figure 6. It ought to be appreciated that the magnet 35 (see Figure 4) in the detent 22 is now aligned with the left-hand sensor 33 (obscured) on the controller 29 with that sensor 33 indicating to the controller 2 that the detent 22 is now in the locked condition. It can be seen from Figure 9 that with the detent 22 in the locked condition the arm 27 of the keeper 6 overlaps the abutment 26 of the detent 22 to thereby prevent movement of the keeper from the closed position.

[0036] Referring now to Figure 7 which illustrates the detent 22 in the released condition whereby the arm 27 on the keeper 6 aligns with slot formed in the detent 22. With the detent 22 in this position the keeper 6 can rotate from the closed position to an open position as illustrated in Figure 8. The keeper sensor 31 (see Figure 4) will sense that the keeper 6 is no longer in the closed position and send a signal to the controller 29 so as to prevent operation of the detent 22 to move it from released condition as illustrated in Figure 8. However once the keeper 6 returns to the closed position as illustrated in Figure 7 the controller 29 can supply power to the electric motor 17 in a reverse polarity rotating the drive shaft 18 in the opposite direction to return the detent 22 to the locked condition.

[0037] It ought to be appreciated from the foregoing that the electric strike 1 according to the invention reduces the likelihood that the keeper 6 will be "locked" in an open condition. Furthermore the inclusion of a super capacitor 36 provides a useful solution to addressing the power failure event.

Claims

CLAIMS:

1 . An electric strike system for use with a door latch assembly including an electric strike assembly including a housing, a keeper that is movable relative to the housing between an open position and a closed position with a biasing means urging the keeper towards the closed position, a detent that is movable relative to the housing between a locked condition and a released condition, a powered actuator that when powered adjusts the condition of the detent, a keeper sensor which senses the position of the keeper, and a controller which controls supply of power to the powered actuator and monitors signals received from the keeper sensor so as to prevent supplying power to the powered actuator while the keeper is in the open position.

2. An electric strike system according to claim 1 including a power storage device within the housing for providing power at least to the controller.

3. An electric strike system according to claim 2 wherein the power storage device includes a super capacitor.

4. An electric strike system according to claim 2 or 3 includes wherein the controller is mounted within the housing, and the electric strike system includes electric terminals for connecting the controller to a main power source external to the housing.

5. An electric strike system according to claim 4 wherein the power storage device is mounted on the controller and provides power to the controller in a power failure event from the main power source.

6. An electric strike system according to claim 5 wherein the controller is operable in a fail-safe mode whereby in the event of the power failure event the power storage device provides power to the controller so as to adjust the condition of the detent to the release condition, or in a fail secure mode whereby in the event of the power failure event the power storage device provides power to the controller so as to adjust the condition of the detent to the locked condition provided the keeper is in the closed position.

7. An electric strike system according to claim 6 including a switch which is adjustable from outside the housing for adjusting operation of the controller between the fail-safe mode and the fail-secure mode.

8. An electric strike system according to claim 7 wherein the switch is operable at a front face of the housing so that the operation of the controller can be adjusted when the electric strike is mounted.

9. An electric strike system according to any one of the preceding claims wherein the keeper sensor includes a hall sensor and the keeper includes a magnet which is sensed by the hall sensor when the keeper is in the closed position.

10. An electric strike system according to any one of the preceding claims wherein the keeper sensor is mounted to the controller.

1 1 . An electric strike system according to any one of the preceding claims including a detent sensor that senses the condition of the detent, and the controller monitors signals received from the detent sensor.

12. An electric strike system according to claim 1 1 wherein the detent sensor includes a pair of hall sensors and the keeper includes a magnet which is sensed by the either hall sensor when the detent is in either locked condition or the released condition.

13. An electric strike system according to claims 1 1 or 12 wherein each detent sensor is mounted to the controller.

14. An electric strike system according to any one of the preceding claims wherein the powered actuator includes an electric motor and a drive shaft that rotates about an actuation axis when energised.

15. An electric strike system according to claim 14 wherein the controller is adjustable in supplying power to the electric motor so as to adjust between operating in a forward mode and a reverse mode so as to rotate the drive shaft in a clockwise and anti-clockwise direction.

16. An electric strike system according to claim 14 or 15 wherein the detent includes a threaded bore and drive shaft includes a threaded portion that is located within the threaded bore of the detent.

17. An electric strike system according to claim 16 wherein the threaded bore of the detent and the threaded portion of the drive shaft interact so that rotation of the shaft causes movement of the detent in the direction of the actuation axis.

18. An electric strike system according to any one of the preceding claims including a security reader for reading a swipe tag.