LOCKSETS

Abstract: A mortice lock for use in an access-control system has a spring bolt 101 which, in the "off-guard" condition of the system, can be withdrawn by handles working a follower 107 to engage the tail 112 of a link bar 110 pinned to the bolt at 111. In the keep assembly 106 there is a double-acting solenoid 114 (Fig 2) which can be pulsed to alternately extend or retract a plunger 115 through a bell-crank mechanism 135. When the system is "off-guard" the plunger 115 is retracted but when "on-guard" the solenoid 114 is pulsed to extend the plunger 115 into an aperture 134 in the lock's forend (Fig 1). Here the plunger 115 engages a lever 130 and pivots the latter up against the link bar 110, which is itself therefore pivoted up about the pin 111. This action places a formation 119 on the top of the link bar against a fixed post 120 in the lockcase to deadlock the bolt against forced retraction and in addition takes the tail 112 of the link bar out of the path of the follower 107, thereby isolating the bolt from the handles .

Description: The present invention relates to locksets. There is described inter alia in our United Kingdom patent specification no. 2161856 a lockset comprising a lock with an extendable and retractable bolt, and a keep assembly for the reception of the bolt when extended; mechanism within the lock for retracting the bolt in response to a user-operable control member, (a handle follower), which mechanism includes a link member movable between positions in which it respectively engages and disengages the operative connection between the bolt and follower; and the keep assembly including an electromagnetic actuator selectively actuable to engage the bolt when received in the keep assembly thereby to resist the retraction thereof, and simultaneously to operate the link member to disengage the operative connection between the bolt and follower. More particularly, the electromagnetic actuator is a double-acting solenoid which is arranged to drive a pin vertically into a slot in the top of the bolt head to deadlock the bolt and simultaneously pivot the link member free of the follower. While this arrangement in general works well there is a limit to the forcing load which the solenoid pin can in practice resist and it is desirable that higher expected forcing loads be resisted in a lock intended, for example, for use in an access-control system within a secure building. Certain problems have also been experienced in maintaining a correct alignment between the solenoid pin and bolt head slot in use of this lockset. The present invention accordingly seeks to provide an alternative lockset in which the above-mentioned drawbacks can be overcome and resides in a lockset comprising a lock with an extendable and retractable bolt, and a keep assembly for the reception of said bolt when extended; mechanism within the lock for retracting the bolt in response to a user-operable control member; a locking member connected to the bolt and movable between positions in which it is respectively engageable with an abutment within the lock so as to deadlock the bolt against forced retraction and free from engageability with said abutment so as to free the bolt for retraction; and the keep assembly including an electromagnetic actuator selectively actuable to operate said locking member when the bolt is received in the keep assembly thus to place said member in the position in which it deadlocks the bolt as aforesaid. In a preferred embodiment said locking member serves also as a link member in the operative connection between the user-operable member and the bolt and disengages that connection when placed in its deadlocking position, similarly in this respect to the link member of our above-described prior lockset, although this is not an essential feature of the invention. Preferably also, the aforesaid locking member is acted upon by a separate actuating member borne within the lock which has a portion lying adjacent to the keep assembly when the door or other closure to which the lock is fitted is closed, (or the locking member itself has such a portion), and which is engageable by the electromagnetic actuator, or a member operated thereby, through an aperture in the case of the lock. An example of a lockset in accordance with the present invention will now be more particularly described with reference to the accompanying drawings, in which: Figure 1 is a vertical section through the lockset shown in an "off-guard" condition; and Figure 2 is a vertical section through the keep assembly of the lockset shown in an "on-guard" condition. Referring Figure 1 the illustrated lockset is in the form of a mortice latch having a bolt 101 biased by a spring 102 to extend from a lockcase 103 through its forend 103A. The bolt 101 comprises a slidable plate 104 up on which is fixed the usual bevelled head 105, so that a door fitted with the latch can slam shut with the bolt head engaging in an associated keep assembly 106. For withdrawing the bolt to permit door-opening there is a rotatable follower 107 within the lockcase which can be turned by handles (not shown) provided on each side of the door. This follower is biased to its rest position shown in the drawing by a spring 108 connected to it through a tie 109. A link bar 110 is pivoted to the bolt by a pin 111, and has a hooked tail portion 112 which in the condition shown in Figure 1 lies in the path of movement of an arm 113 extending from the follower 107. Accordingly, turning the follower 107 clockwise (in the sense of the drawing) by either of the external handles causes the arm 113 to pick up the tail 112 of the bar 110 and thereby withdraw the bolt from the keep assembly 106 through the bar 110 and pin joint 111. Thus it will be seen that in the "off-guard" condition depicted in Figure 1 the lock functions as a normal doorlatch permitting passage through the doorway by any person operating the follower 107. In addition to these components within the lockcase 103 there is a lever 130 pivoted on a pin 131. In the illustrated "off-guard" condition of the lock one arm 132 of this lever lies directly beneath the link bar 110 while its other arm 133 lies in an aperture 134 in the forend 103A and thus faces the keep assembly 106 when the door is closed. The keep assembly 106 of this lockset houses a double-acting solenoid unit 114 (Figure 2). This solenoid unit is used to drive, through a bell-crank 135 pivoted at 136, a horizontally-reciprocable plunger 115, shown in its retracted (leftward) position in Figure 1 and in its extended (rightward) position in Figure 2. The solenoid unit in this example is equipped with a pair of solenoids acting in opposite directions upon a core 114A connected to the bell-crank 135 and arranged to retain the plunger 115 in whichever of its two positions it has been set until the next actuation of the appropriate solenoid's field coil(s). In the retracted position of the plunger, as shown in Figure 1, it has no effect upon any other part of the lock mechanism, so that the mechanism remains free for operation as a simple latch as described above. If, however, with the door closed and the bolt head 105 accordingly received in the keep assembly the solenoid unit 114 is actuated to drive the plunger 115 to its extended (rightward) position, the end of the plunger is caused to enter through the aperture 134 in the lock forend and pivot the lever 130 about the pin 131 - anti-clockwise in the sense of the drawing - by abutment with the arm 133. This causes the other arm 132 of the lever to engage the link bar 110 and pivot the latter in the same sense about its own pin 111. In so doing, an upstanding nose formation 119 on the top of the bar 110 is placed adjacent to a fixed post 120 in the lockcase so that the post 120, lying in the path of the formation 119 in the sense of retracting movement of the bolt 101, will act to deadlock the bolt against forced retraction. In addition, the end 112 of the bar will be lifted clear of the path of the follower arm 113, so if the follower is turned by a person operating either door handle no load can be transmitted to the bolt. If, however, an attempt is made by some other means to put force on the bolt 101 in its retracting direction, this will be securely resisted by the nose 119 of bar 110 engaging the post 120 as stated above. In practice, the illustrated lockset forms part of an electronic access-control system for the door to which it is fitted intended to operate at different levels of security at different times. That is to say during "off-guard" periods access is permitted through the doorway to all persons encountering the door. During "on-guard" periods, however, access is to be restricted only to duly authorised personnel. The "off-guard" and "on-guard" periods may be preprogrammed (for example to accord with the normal opening times of a suite of offices) and/or selectable at will at a central control station, in accordance with the parameters of the particular system installed, the details of which do not form part of the present invention. Suffice it to say, when the lock is to be "off-guard" the solenoid unit 114 is pulsed to retract the plunger 115 to its Figure 1 position and the mechanism then operates in its above-described latch mode. When it is required to be "on-guard" the opposite-acting solenoid in the unit 114 is pulsed to extend the plunger 115 into engagement with the lever 130 and thereby deadlock/ disengage the mechanism also as described above. In this condition access can only be obtained through the door on receipt of a signal to retract the plunger 115 once more. This may be derived for example from an associated infra-red or magnetic card reader on the outside of the doorway, or from any other suitable code-input device known to those skilled in the art, it being understood that the code to enable retraction of the plunger 115 in this mode will be issued only to those persons authorised to gain access during this period. Retracting the plunger 115 back into the keep assembly of course releases the bar 110 from the post 120 and reestablishes the operative connection between the bolt and the door handles. After any authorised door-opening during an "on-guard" period the solenoid unit 114 is automatically pulsed again on closure of the door to return the plunger 115 into engagement with the lever 130. For this and for other monitoring purposes micro-switches (not shown) may be fitted in the keep assembly 106 to detect the presence or absence of the bolt head within the keep and to detect in which of its two positions the plunger 115 lies at any time. The position of the bolt may alternatively be sensed by means of a magnet 137 within the bolt head operating a reed contact in the keep assembly. For emergency opening of the door in the event of an electrical power failure occurring with the plunger 115 deadlocking the mechanism, a lever or other suitable manually-operable device (not shown), accessible only from the inside of the doorway, may be provided on the keep assembly to retract the plunger. Figure 2 also illustrates an option for bypassing the electrical operation of the lock from the outside by means of a key-operated locking cylinder 138 mounted in the keep assembly whose thrower 139 can operate the plunger 115 through an arm 140 attached to the lower end of the solenoid core 114A. In a variant of the illustrated lock, instead of employing a separate lever 130 for operation of the link bar 110, these elements could be effectively combined in one piece with the bar 110 therefore having a portion extending down into the aperture 134 for direct engagement by the plunger 115.

Claims: 1. A lockset comprising a lock with an extendable and retractable bolt (101), and a keep assembly (106) for the reception of said bolt (101) when extended; mechanism (110) within the lock for retracting the bolt (101) in response to a user-operable control member (107), and an electromagnetic actuator (114) in the keep assembly (106) selectively actuable to cause the bolt (101) to be deadlocked against forced retraction; characterised by a locking member (110) connected to the bolt (101) and movable between positions in which it is respectively engageable with an abutment (120) within the lock so as to deadlock the bolt (101) against forced retraction and free from engageability with said abutment (120) so as to free the bolt (101) for retraction; and the said electromagnetic actuator (114) is selectively actuable to operate said locking member (110) when the bolt (101) is received in the keep assembly (106) thus to place said member (110) in the position in which it deadlocks the bolt (101) as aforesaid. 2. A lockset according to claim 1 wherein said locking member (1 10) serves also as a link member in the operative connection between the user-operable member (107) and the bolt (101) and disengages that connection when placed in its deadlocking position. 3. A lockset according to claim 2 where said locking member (110) is in the form of an element pivoted to the bolt (101), engageable at one position (112) by a rotatable said user-operable control member (107), and bearing a formation (119) at another position for engagement with said abutment (120), whereby in one pivotal position said member (110) is engageable at said one (112) position with said control member (107) and free from engageability at said other position (119) with said abutment (120) and in another pivotal position said member (110) is engageable at said other position (119) with said abutment (120) and free from engageability at said one position (112) with said control member (107). 4. A lockset according to any preceding claim wherein said locking member (110) is acted upon by a separate actuating member (130) borne within the lock which has a portion (133) lying adjacent to the keep assembly (106) when the closure to which the lock is fitted is closed, and which is engageable by the electromagnetic actuator, or a member operated thereby (115), through an aperture (134) in the case (103) of the lock. 5. A lockset according to any one of claims 1 to 3 wherein said locking member (110) has a portion lying adjacent to the keep assembly (106) when the closure to which the lock is fitted is closed, and which is engageable by the electromagnetic actuator, or a member operated thereby (115), through an aperture (134) in the case (103) of the lock. 6. A lockset according to any preceding claim wherein said electromagnetic actuator (114) is arranged with a generally vertical line of action in the keep assembly (106) and is arranged to drive a plunger (115) of the keep assembly (106) with a generally horizontal line of action to operate the locking member (110) as aforesaid, through motion-transmitting means (135). 7. A lockset according to any preceding claim comprising key-operable means (138) associated with the keep assembly (106) capable of releasing said locking (110) member from its deadlocking position when the bolt (101) is received in the keep assembly (106), without energization of said electromagnetic actuator (114). 8. An access-control system in which a lockset in accordance with any preceding claim is fitted to a closure; comprising means effective to actuate said electromagnetic actuator (114) to place said locking member (110) in its deadlocking position during selected periods; and further comprising means effective to actuate said electromagnetic actuator (114) to release said locking member (110) from its deadlocking position during such periods only in response to the recognition of a correct code presented to the system.

Inventors: HORDIJK, JOHAN CORNELIS
Applicants: CHUBB LIPS NEDERLAND BV
Application year: 1987
Main classification: E05B47
IPC codes: E05B47