WO1993006325A1

WO1993006325A1 - Locks

Info

Publication number: WO1993006325A1
Application number: PCT/GB1992/001766
Authority: WO
Inventors: Conrad Raymond Crewe Maloney; Roger David Swadling
Original assignee: Newtronics SA
Current assignee: Newtronics SA
Priority date: 1991-09-26
Filing date: 1992-09-25
Publication date: 1993-04-01
Anticipated expiration: 1994-03-26
Also published as: GB9120512D0; AU2595992A

Abstract

Door latches and door locks electrically remotely controllable from a locking or latching condition to an unlocked state have two solenoids in them. Actuation of one solenoid releases locking or latching and actuation of the other applies locking or latching. By the use of two solenoids, each for the specific task, only a brief signal has to be sent to the lock or latch unit rather than supplying continuous power to hold a lock or latch openable in known fashion. The invention may be applied to electrically controllable latch plates for controlling remote entry units or e.g. incorporated in mortice locks used for doors in hotel or office buildings.

Description

LOCKS

This invention relates to locks, and more specifically to electrically-controlled locks.

Locks of the types most commonly known for securing buildings have been known since the middle ages. It was once the case that an acceptable level of security could be maintained for a building by the simple issue of keys to enable the actuation of the locks, and entry to the building. In recent years the increase in size of buildings which are used by a large number of different users for short periods, such as hotels, blocks of flats with security doors, and office buildings with a plurality of different occupying companies, has rendered the issuance of multiple copies of keys cumbersome and incapable of maintaining an acceptable level of security.

The solution to this problem has been to equip these buildings with locks that may be electrically controlled from a remote source. These locks generally contain a solenoid or electromagnet and prevent entry when no current is passing through the solenoid or electromagnet; on actuation, the solenoid enables the lock to be opened and entry gained.

Such locks are expensive to install and run because of the large amounts of power needed to keep the lock activated. This high usage of power also generates considerable amounts of heat, which is generally undesirable, and limits the period for which a lock may be held open.

According to the present invention there is provided a remotely-operable door latch comprising a latch member able to be moved between a projecting latching position and a retracted unlatching position by electrical control means comprising first and second solenoids arranged to act on a release member movable between a first position in which the latch is locked, and a second position in which it is unlatched, and being biased towards the first position, wherein actuation of the first solenoid moves the release member away from the first position and into the second position in which it becomes latched by the second solenoid, and wherein actuation of the second solenoid releases such latching and allows the release member to return to its first position.

Such a lock may be remotely controlled by electronic means. In a particular preferred embodiment, the electronic means will, on a signal from the user, activate the first solenoid, detect the armature of the first solenoid reaching the end of its travel by the back electromagnetic force generated, and deactivate the first solenoid; if desired, the electronic means may, after a predetermined period, activate the second solenoid until the back electromagnetic force, generated from the armature of the second solenoid as it reaches the end of its travel, is detected, whereupon the second solenoid is deactivated.

A variation of the present invention, for situations where it is not desired to have the lock openable only from the outside for a short period, is when the electronic control means activates the second solenoid only on receipt of a second signal from the user.

The advantages of the present invention over those types of lock which are known are that the solenoids are activated for only a brief period, and thus consume little power and generate little heat. The lock may be maintained in either the "locked" or "unlocked" state for as long as desired, and may be returned to the locked state either automatically or when desired by the user. If the lock is set up to be returned to the locked state by the user then, if the user is unsure whether the lock is in the "locked" state, the sending of the second signal by the user will ensure that the lock either stays "locked" or moves to the "locked" position.

The term 'solenoid' as used herein is intended to cover both a solenoid produced as a unitary component, usually consisting of a coil and a movable ferromagnetic member, and an arrangement consisting of a coil, usually with a fixed iron core, positioned to cooperate with a ferromagnetic member which may form part of the mechanism of the lock, and which may be attracted towards the coil when a current is passed through the coil.

The present invention will be further explained by way of example with reference to the accompanying drawings in which: Figure 1 shows a mortice lock embodiment of the present invention in its locked state;

Figure 2 shows the Figure 1 embodiment of the present invention in its unlocked but still-engaged state;

Figure 3A and 3B shows details of a release lever shown in Figures 1 and 2 when the lock is in its "locked" and "unlocked" states respectively;

Figure 4 shows a releasable latch embodiment of the present invention in its unlatched state;

Figure 5 shows another embodiment of the present invention in its unlatched state;

Figure 6 shows the embodiment of Figure 5 in its unlatched state;

Figure 7 shows another embodiment of Figure 5 in its unlatched state, and

Figure 8 shows the embodiment of Figure 7 in its latched state.

According to Figures 1 and 2, a lock 2 mounted in door 1 comprises a case 4 within which are mounted a latch bolt 6 and a dead bolt 8. Bolt 6 is biased by way of a spring (not shown) to extend out of case 4. Latch bolt 6 comprises a head 24, a shaft 26 and an end plate 28, the end plate 28 being substantially perpendicular to the axis of movement of the latch bolt 6. Latch bolt 6 is retracted into the case 4 by the action of a lever 10 against the headwards face of end plate 28. Lever 10 is part of a cam 14, which is rotatable by a square shaft 16. Cam 14 is rotated in a clockwise direction (as viewed) to engage lever 10 with end plate 28. Mounted on shaft 16 are handles (not shown) for use when door 1 is to be opened.

Dead bolt 8 comprises a head 30 and a plate 32. Projecting from head 30, substantially perpendicular to it and to the axis of movement of the dead bolt 8, is a pin 34. A stop 36 mounted on case 4 and extending into a slot 38 in the plate 32, defines the limits of the movement of the dead bolt 8. Pin 34 is captive in a slot 42 in a lever 40 pivoting about a pivot 44, and having a cam face 46. A nose 12 forming part of the cam 14 acts on face 46, when cam 14 is rotated in a clockwise direction (as viewed), to retract the dead bolt 8 into the case 4.

Lever 10 is biased in the anti-clockwise direction against a stop 20 by a spring 18 and nose 12 is biased, via lever 10 and cam 14, against a stop 22.

The status of lock 2, that is "locked" or "unlocked", is controlled by a release lever 48 mounted on a pivot 50.

When the lock is locked, a nose 52 (seen more clearly in Figure 3) of release lever 48 is engaged in a recess 54 in the edge face of the cam 14, preventing clockwise rotation of the cam 14.

The position of release lever 48 is determined by two solenoids 56 and 64, having armatures 58 and 66 respectively, and a compression spring 62. Armatures 58 and 66 act on the release lever 48. Armature 58, acting in a direction substantially tangential to the arc of movement of the release lever 48, is attached to release lever 48 at point 60. Armature 58 is configured such that it pulls release lever 48 out of contact with cam 14 on activation of solenoid 56. Attached between armature 58 and a node (not shown) extending from case 4, and biasing the locking lever 48 into the recess 54, is the compression spring 62.

Referring to Figures 3A and 3B, when the lock is in a locked state, armature 66 which is biased to project from solenoid 64, is held within the solenoid. The face of armature 66 abuts an edge face 70 of the release lever 48. The compression spring 62 prevents the nose 52 of the release lever 48 from disengaging from recess 54 in the cam 14.

Activation of solenoid 56 moves armature 58 so that release lever 48 is pivoted about pivot 50 in a clockwise direction. The edge face 70 of lever 48 slides over the face of armature 66 until it ceases to abut that face, after which the armature 66 moves under its bias to project into a recess 72 in lever 48, latching it in a clockwise limit position. On deactivation of solenoid 56, armature 58 is biased by compression spring 62 to pivot release lever 48 in an anticlockwise direction. This movement is prevented by armature 66 remaining within the recess 72.

The lock is now in an "unlocked" state and the latch bolt 6 and dead bolt 8 may be retracted into the case 4 and the door 1 may be opened, by clockwise rotation of square shaft 16.

To return the lock 2 to a "locked" state, solenoid 64 is activated to withdraw armature 66 into it and clear of recess 72. The compression spring 62 moves the release lever 48 anticlockwise so that nose 52 moves to a position to engage in the recess 54 in the cam 14. The door may no longer be opened.

A pivoted latch plate embodiment is shown in Figure 4. A latch plate 80 is pivotally mounted in a casing 82 so that the latch 80 may partially rotate about its axis 83 until an edge 88 of latch plate 80 projects out of casing 82.

The casing 82 is mounted in a doorframe 84 so that latch 80 is located on an inner face of the doorframe 86, with edge 88 projecting into the door space. Latch 80 is biased so that edge 88 projects by the maximum amount into the door space. When latch 80 is pivoted from the position shown, edge 88 is withdrawn from the door space. A cam 90 projects from the opposite side of latch 80 to edge 88. An operating arm 92 rotating about a stud 94 and biased to rotate in an anti-clockwise direction (as viewed) by a compression spring 96, is in contact with the cam 90 at a cam surface 98.

Cam 90 and surface 98 are configured so that, on rotation of latch 80 from the illustrated projecting position, they slide over each other and arm 92 is rotated in a clockwise direction.

An actuator arm 100 pivoted about a stud 102 is biased by a compression spring 104 to interact with the free end of arm 92. Tooth 106 on arm 100 engages with face 108 on the end of arm 92 to prevent clockwise rotation of arm 92 when the latch is engaged.

Pivoted on stud 102 is an armature 112 of a solenoid 114. Armature 112 is configured so that the activation of solenoid 114 pulls activating arm 100 out of the path of arm 92.

A solenoid 116 with an armature 118 is attached to the casing 82. Armature 118 is biased away from the solenoid 116 and is configured so that when solenoid 116 is activated armature 118 moves into the solenoid 116 taking with it a detent 119 movable with the armature. The free end 120 of the detent projets into the path of the lever 100.

Solenoid 116 is positioned so that when the actuator arm 100 engages the free end of arm 92, the end 120 of the detent 119 rests against an end face of the arm 100.

To change the latch from its engaged state to its unlatched state, as shown in Figure 4, solenoid 114 is activated, whereon armature 112 pulls 100 away from its engagement with arm 92. End 120 of the detent slides across the end of arm 100 until they no longer abut, and end 120 then moves towards stud 102 until it contacts a detent face 122 at the end of arm 100. The biasing of armature 118 takes effect, and armature 118 moves so that detent 119 latches arm 100 in a position where it cannot interfere with arm 92. The latch is now "disengaged".

To reengage the latch, solenoid 116 is activated, drawing armature 118 and detent 119 to the solenoid and ceasing to latch arm 100. Compression spring 104 returns actuating arm 100 into a position where it is in the path of arm 92, and the latch is again in an "engaged" state.

Referring to Figures 5 and 6, a third embodiment is the same as the second embodiment shown in Figure 4, with the following differences.

A leaf spring 130 is attached by suitable means to the casing 82 at a point 134. Leaf spring 130 is so configured that in an unstressed state an end 132 rests in a position adjacent to, and in the path of, the end of the arm 100, so preventing arm 100 from interfering with the pivotal movement of operating arm 92.

An electromagnet 136 with a core 138 is attached to the casing 82 (attachment means not shown) in such a position that the core 138 is adjacent the leaf spring 130 at a region 140.

From an "unlatched" state as shown in Figure 6, activation of the electromagnet 136 causes region 140 of the spring to become attracted to, and move towards, the core 138. This movement causes the end 132 to move to a position where it is outside the path of movement of arm 100. Actuation arm 100 is biased clockwise by spring 104 and pivots to a position where it interferes with operating arm 92. When the electromagnet 136 is deactivated, end 132 is biased into contact with the end face of the actuating arm 100.

To "unlatch" the latch, solenoid 114 is activated, whereon armature 112 pulls arm 100 into a position where it is clear of arm 92. End 132 ceases to abut the end of arm 100 and the bias of spring 130 moves end 132 of the spring 130 back into a position where it is within the path of the end of the arm 100, to prevent it from interfering with movement of the arm 92. The latch is now "unlatched" .

In that embodiment of the invention shown in Figure 7 and 8, the latch mechanism includes a pair of solenoids 114 and 116. The arm 100 of the latch mechanisms shown in Figures 4 to 6 are replaced by a bent lever 130 pivoting about a shaft 102. The armature of each solenoid is connected to an arm of lever 130 on each side of the fulcrum provided by shaft 102. The connection between each armature and the leaver is such as to permit rotational movement of the lever and longitudinal movement of the armature. The end 132 of the longer arm of lever 130 is formed with a recess adapted to be engaged by a detent spring 134 in order to hold the arm 130 in the position in which its tooth 106 is out of the path of movement of the free end- of arm 92, which is the unlatched or disengaged position shown in Figure 7. In this position, the latch is kept in its position projecting from casing 82 by spring 96, by the inter- engagement of cam 90 and follower surface 98.

When the latch is to be moved to its latched position shown in Figure 8, the solenoid 114 is energised to pivot lever 130 clockwise as viewed against the restraining force of springs 104 and 134. This brings the tooth 106 into abutment with face 108 on arm 92, thus preventing the latch plate 80 from pivoting about axis 83 to its unlatched position. When the solenoid 114 is deenergised, the lever 130 is held in the latched position, against the force of spring 104 by the contact between the end of detent spring 134 and end 132 of lever 130. This detaining force is able to be overcome by actuation of solenoid 116 to move the latch to the unlatched position shown in Figure 7.

Accordingly it will be seen that the present invention provides locking devices which may be selectively disabled by means of short pulses of current effective to operate a selected solenoid forming part of the lock or latch. As mentioned above, the operating pulses would usually be supplied alternately to the two solenoids, but a second successive pulse to the same solenoid would have no effect on changing the state of the latch or lock. Thus the present invention provides a remotely-operable lock or latch which consumes no electrical energy when in either of its stable operating states.

Claims

1. A remotely-operable door latch comprising a latch member able to be moved between a projecting latching position and a retracted unlatching position by electrical control means comprising first and second solenoids arranged to act on a release member movable between a first position in which the latch is locked, and a second position in which it is unlatched, and being biased towards the first position, wherein actuation of the first solenoid moves the release member away from the first position and into the second position in which it becomes latched by the second solenoid, and wherein actuation of the second solenoid releases such latching and allows the release member to return to its first position.

2. A latch according to claim 1, adapted to be mounted in a door, wherein the latch comprises a latch member which protrudes from the lock casing to engage in a recess in a door frame, and a rotatable shaft which may, via a cam and lever mechanism, withdraw the latching member into the lock casing, the release member being a pivotable lever acted upon by the two solenoids, wherein activation of the first solenoid allows a pawl mounted on the release lever to move from a position in which the pawl engages a cam to prevent rotation of the cam, to a position clear of the cam; and

activation of the second solenoid returns the release lever to its former position, and the first solenoid latches it in that position.

A latch as claimed in claim 2, including a dead bolt adapted to be held within the latch casing when the latch is engaged, and to be movable to a projecting position when the latch is disengaged.

A latch according to claim 1 adapted to be mounted in a door frame, comprising a pivotable latch plate, an operating arm, and an actuating arm, wherein

the actuating arm is acted upon alternatively by the solenoids;

the operating arm is biased against the latch plate, so that pivotal movement of the latch plate moves the operating arm angularly;

the actuating arm is biased to a position in which it prevents angular movement of the operating arm;

and activation of the first solenoid moves the actuation arm into a position in which it is out of the path of the operating arm, and is latched there by the second solenoid, activation of the second solenoid returning the actuator arm to its former position.

5. A latch adapted to be mounted in a door, and comprising a latch member adapted to protrude from the latch body to engage in a recess in a door frame, and a rotary shaft which may, via a cam and lever mechanism, withdraw the latch member into the latch body, and a release member which is a pivotable lever acted on by a pair of solenoids, wherein activation of the first solenoid allows a pawl mounted on the release lever to move from a position in which the pawl engages a recess in the cam to prevent rotation of the cam, to a position clear of the cam, and in which activation of the second solenoid returns the release lever to its first position in which it is latched by the first solenoid.

A lock according to claim 1 and substantially as hereinbefore described with reference to any of the accompanying drawings.