GB2196378A - Disabling locking mechanisms - Google Patents

Description

1 GB2196378A 1 SPECIFICATION since only a pulse of magnetising energy is

required to reverse and retain the polarity of Locking mechanisms the magnetisable element little power is con sumed in switching the actuator between its The present invention relates to locking 70 two states, as distinct from e.g. the conven mechanisms. More particularly, though not ex- tional solenoid which consumes power for the clusively, the invention seeks to provide an whole of the time that it is in the -energised electromechanical locking mechanism which state. Furthermore, by remaining magnetised can be used in an electronically-controlled co- with the last-induced polarity between pulses derecognition lock for safes and the like secu- 75 the magnetisable element in effect -remern rity enclosures, which is mechanically simple bers- its most recent command so that, for and highly reliable in operation, and operable example, if the actuator is blocked or other with minimal power consumption. wise restrained from moving into its position In one aspect the invention accordingly reappropriate to that command at the instant sides in a locking mechanism comprising a 80 when the corresponcing pulse is given, it will bolt or other such locking member movable nevertheless move into and remain in the cor between locking and unlocking positions; a rect position under the remanent magnetic infl manually or otherwise operable control mem- uence as soon as the aforesaid restraint is ber adapted to be coupled to the locking removed, without having to be pulsed again at member for moving the latter between its 85 that time. The particular advantages of this locking and unlocking positions; and an elec- characteristic in the context of an actuator for tromechanical actuator arranged for selectively use in a preferred safe lock mechanism will disabling or enabling the coupling of the con- appear from the ensuing description.

trol member to the locking member such as to In a preferred embodiment of the aforesaid move the latter from its locking to its unlock- 90 mechanism the control member is in the form ing position. of a rotatable disc or sector having a coupling In a preferred embodiment said actuator notch in its periphery, and an arm is articu- comprises first magnetic means including an lated to the locking member having a head element of magnetisable material and means adapted to engage in said notch; in the lock for applying a pulsed magnetising field thereto, 95 ing position of the mechanism the head of the said magnetisable material being such that said arm lying in a position out of driving en said element is capable of repeated reversals gagement with said notch and preferably of its magnetic polarity in response to the facing an abutment to resist forced movement application thereto of magnetising pulses of of the locking member towards its unlocking reverse senses and is capable of remaining 100 position; and said actuator serving in a first magnetised with the last-induced polarity be- position to block movement of said head into tween such pulses; and second magnetic driving engagement with said notch such as to means for providing a predetermined magnetic enable the control member to move the lock field to interact with the remanent magnetism ing member to its unlocking position.

of said element; whereby said actuator is 105 These and other aspects of the present in- baised by the magnetic interaction between vention will now be more particularly de said element and said second magnetic means scribed, by way of example, with reference to to move to a first or a second position re- the accompanying drawings, in which:

spectively to disable or enable said coupling Figure 1 shows the mechanism of an elec- of the control member to the locking member, 110 tronically-controlled safe lock, with its cap re in dependence upon the sense of the last- moved, in the locked condition; applied said pulse. Figure 2 is a similar view of the mechanism Typically, the magnetisable element in the of Figure 1, in the condition in which it has aforesaid actuator may be in the form of a bar been freed for unlocking; pivoted at one end and surrounded by a coil 115 Figure 3 is a similar view of the mechanism through which the magnetising pulses are ap- of Figures 1 and 2, in the unlocked condition; plied, while the aforesaid second magnetic and means comprise a permanent magnet defining Figure 4 is a sectional view, to an enlarged opposed poles between which the opposite scale, through the electromechanical actuator end of the bar lies, whereby the bar is. influ- 120 of the mechanism of Figures 1 to 3.

enced at any instant to pivot towards one or The lock shown in the drawings is intended other of the permanent magnet poles in deprincipally for use in locking the main boltwork pendence upon the sense of the last-induced of a safe or vault door, and its layout and polarity of the bar. The said opposite end of dimensions are chosen so that the unit may the bar, or a member carried by it, can there- 125 be interchangeable with known keyless combi fore serve as an abutment to block or free the nation locks, such as that marketed by the aforesaid coupling of the control member to present applicants under the designation 71-08.

the locking member in the two respective It has a bolt 1 which can be extended and pivotal positions of the bar. retracted from the case 2 and to which a In use of an actuator as defined above, 130 drop-arm 3 is pivoted at 4. The arm 3 has a 2 GB2196378A 2 laterally-extended head 5 at its end opposite sponse to pulses of electricity passed through to its connection with the bolt, which in the the associated coil 13 in opposite directions.

normal locked condition of the mechanism il- For example, if it is assumed that the magnet lustrated in Figure 1 lies on the periphery of a-- pole P1 is a North and P2 a South ' then if an rotatable disc 6, onto which it is drawn by a 70 electrical pulse is sent through the associated spring schematically indicated at 7. In this coil 13 in the direction such as to induce a condition the head 5 faces a fixed abutment 8 North pole at the bottom end of the Chromin in the lock case to resist forced retraction of dur element 11 A within the coil and a South the bolt 1. pole at the top end of that element between The disc 6 is freely rotatable by hand 75 the poles P 'I and P2, then the element will be through the agency of an external knob or attracted by pole P1 and repelled by pole P2 handle (not shown), within limits set by a stop so as to pivot the actuating member into the 9A, but is normally held lightly in the rest position in which it is shown in Figure 1, be position shown in Figure 1 by means of a ing its locking position. The remanence of the detent spring (not shown). It has a notch 10. 80 element 11 A is sufficient to keep the actuat in its periphery which, when the disc is turned ing member in that position until an electrical anti-clockwise (in the sense of the drawing) pulse is sent through the coil 13 in the oppo away from its rest position underlies the head site direction, whereupon the induced polarity of the drop-arm, and into which the head is of the element 11 A is reversed so that its biased to engage by the spring 7 so as to 85 end between the poles P1 and P2 now be establish a drive connection between the disc comes a North, and it will be influenced oppo 6 and bolt 5. Normally, however, the head 5 sitely by the permanent magnet poles to pivot is blocked from moving into full engagement the actuating member into the position in with the notch 10 and free of the abutment 8 which it is shown in Figure 2, being its re by the presence of the- actuating member 11 90 lease position.

of a bistable electromechanical actuator 12. In use, magnetising pulses are supplied to The actuator 12 is similar to the actuators the coil 13 from an electronic control circuit shown in our copending United Kingdom pa- (not shown) associated with a code-input or tent application No. 2142374, comprising a recognition device such as a numeric keypad, magnetising coil 13 within which the actuating 95 card-reader, biometric sensor or the like, so member 11 is pivoted, and a rectangular that the coil 13 is pulsed to move the actuat horseshoe permanent magnet 14 surrounding ing member out of its Figure 1 position and the coil 13, with the actuating member ex- into its Figure 2 position only when a correct tending through the gap between the poles of code or other indication of the user's authority the permanent magnet. That part of the actu- 100 to operate the lock has been entered. A tim ating member 11 which extends within the ing circuit may also be included to restrict coil 13 and between the associated perma- possible operation of the actuator to its re- -nent magnet poles is made from a magnetisa- lease position only to specified periods of the ble material having a low energy requirement day.

for reversing its magnetic polarity coupled 105 Assuming that the actuator has been flipped with a high remanence, such as a heat-treated to its release position, the disc 6 can now be element of the cobalt-iron-vanadium alloy mar- turned to pick up the drop- arm 3 as shown in keted by Telcon Metals Limited under the Figure 2. Turning the disc further anti name -Chromindur-. clockwise (in the sense of the drawing) there- An example of the construction of an actua- 110 after retracts the bolt 1 to the Figure 3 posi- tor 12 for use in this lock mechanism is tion, through the coupling established between shown in Figure 4. A bar 11 A (which may be the drop-arm head 5 and notch 10.

laminated) of Chromindur is fitted at one end The operation of the control circuit may pro- with a plastics cap 11 B by which it is pivo- vide for an unlocking--- window-of limited du tally borne in a pair of recesses 13B formed 115 ration following operation of the actuator 12 inside the coil bobbin 13A. The bar 11 A ex- to its release position, after which the coil 13 tends out of the bobbin 13A to lie between will be automatically pulsed again to return the the poles P1 and P2 of the associated field member 11 to its locking position (shown in magnet 14 and its upper end is fitted with a dotted line in Figure 3), or a separate locking plastics tip piece 11 C. The actuator is assem- 120 pulse may be given under user control. The bled by passing the Chromindur bar 11 A with bolt 1 can be thrown out again, (either before its cap 11 B through the bottom of the coil or after the actuator has been flipped back to bobbin 13A and snapping on the tip piece its locking position), by turning the disc 6 11 C. The coil is then assembled to the mag- clockwise to drive the drop- arm 3 rightwards net 14 which retains the actuating member 125 through the engagement of its head 5 in the against ejection through the bottom of the notch 10. In doing so, if the actuator has bobbin. already been flipped back to its locking posi- The actuating member 11 can be flipped tion the head 5 will come up against the side between two positions (as indicated by corn- of the actuating member 11 and displace it paring its positions in Figures 1 and 2) in re- 130 temporarily back to its release position, the 3 GB2196378A 3 mechanism passing through a condition equi- of magnetising pulses of reverse senses and valent to that shown in Figure 2 at this point. is capable of remaining magnetised with the From this condition, continued clockwise rota- last-induced polarity between such pulses; and tion of the disc 6 will serve to throw out the second magnetic means for providing a pre drop-arm head 5 from the notch 10 through 70 determined magnetic field to interact with the the action of the cam surfaces 5A and IOA of remanent magnetism of said element; whereby these elements, so that the disc and drop-arm said actuator is baised by the magnetic inter return to the relationship shown in Figure 1. If action between said element and said second the locking pulse has already been given, as magnetic means to move to a first or a sec- soon as the head 5 rises clear of the end of 75 ond position respectively to disable or enable the actuating member 11 the latter will flip said coupling of the control member to the back to its locking position by the interaction locking member, in dependence upon the r of its remanent magnetism with the field of sense of the last-applied said pulse.

the permanent magnet 14. Otherwise, it will 3. A mechanism according to claim 2 move back to its locking position when the 80 wherein said magnetisable element is in the subsequent locking pulse is given. It will be form of a bar pivoted at one end and sur seen that the actuating member 11 is not rounded by a coil through which the magnetis loaded by the drop-arm in the normal locked ing pulses are applied, while the aforesaid condition of the mechanism. second magnetic means comprise a perma- It has been mentioned that during the time 85 nent magnet defining opposed poles between between pulses through the actuator coil 13, which the opposite end of the bar lies, the last-induced polarity of the magnetisable whereby the bar is influenced at any instant to element 11 A is retained, so that this polarity pivot towards one or other of the permanent serves effectively as a---memory-of the most magnet poles in dependence upon the sense recent command signal, i.e.---lock-or---re-90 of the last-induced polarity of the bar.

lease---. The potential importance of this char- 4. A mechanism according to claim 3 acteristic during the bolt-throwing sequence of wherein the opposite end of said bar, or a the illustrated lock has already been explained. member carried by it, serves as an abutment It is also of importance in the following cir- to block or free the aforesaid coupling of the cumstances. That is to say it may occur that 95 control member to the locking member in the at the time when a -release- command is two respective pivotal positions of the bar.

given a user may have already turned the disc 5. A mechanism according to any preceding 6 from the Figure 1 position to align the claim wherein the control member is in the notch 10 with the head 5, so that the drop- form of a rotatable disc or sector having a arm is resting on the actuating member 11 100 coupling notch in its periphery, and an arm is and the latter is prevented from moving at the articulated to the locking member having a instant when the coil 13 is pulsed to reverse head adapted to engage in said notch; in the its polarity. However, the magnetic influence locking position of the mechanism the head of on the actuating member remains so that as said arm lying in a position out of driving en soon thereafter as the disc 6 is turned again 105 gagement with said notch; and said actuator to lift the drop-arm slightly the actuator will serving in a first position to block movement flip over to its -release- position and the bolt of said head into driving engagement with 1 can be withdrawn, without any further ener- said notch such as to enable the control mem gisation of the coil 13. ber to move the locking member to its unlock 110 ing position.

Claims (2)

CLAIMS 6. A mechanism according to claim 5

1. A locking mechanism comprising.a bolt wherein in the locking position thereof the z or other such locking member movable be- head of said arm faces an abutment to resist tween locking and uhlocking positions; a manforced movement of the locking member to- ually or otherwise operable control member 115 wards its unlocking position.

adapted to be coupled to the locking member 7. A locking mechanism substantially as pr moving the latter between its locking and hereinbefore described with reference to the unlocking positions; and an electromechanical accompanying drawings.

actuator arranged for selectively disabling or enabling the coupling of the control member Published 1988 at The Patent Office, State House, 66/71 High Holborn, London WC 1 R 4TP. Further copies may be obtained from to. the locking member such as to move the The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD.

latter from its locking to its unlocking position. Printed by Burgess & Son (Abingdon) Ltd. Con. 1187.

2. A mechanism according to claim 1 wherein said actuator comprised first magnetic means including an element of magnetisable material and means for applying a pulsed mag netising field thereto, the said magnetisable material being such that said element is capable of repeated reversals of its magnetic polarity in response to the application thereto