1 A LOCK ASSEMBLY Field of the Invention [0001] The present invention relates to a lock assembly, in particular an electrically powered lock assembly with a solenoid driver. Background of the Invention [0002] Electrically powered locks are known which include a plunger driven by a solenoid. The plunger is driven by the solenoid between a locking configuration, in which it prevents torque applied to a lock hub from retracting a lock bolt, and an opening configuration, in which torque applied to the lock hub retracts the lock bolt. [0003] A disadvantage of such locks is that it is possible to open them whilst they are locked with an externally applied magnetic force. This is because the plunger is made of a ferrous metal, usually steel. It is thus possible to open a locked door by moving a magnet in the vicinity of the lock, in a direction which draws the plunger away from the out of engagement with the lock hub. [0004] One known approach to attempt to solve this problem includes positioning magnetic shielding material around the plunger and solenoid. However, the disadvantage of this approach is that it increases the size of the lock, or alternatively reduces the space available inside the lock. The shielding also adds to the expense of the lock. Object of the Invention [0005] It is the object of the present invention to substantially overcome or at least ameliorate one or more of the above prior art disadvantages. Summary of the Invention [0006] Accordingly, the present invention provides a lock assembly including: a hub operatively associated with a lock bolt; 2 a solenoid adapted for configuring in a locking configuration, preventing torque applied to the hub from retracting the lock bolt, or an opening configuration, allowing torque applied to the hub to retract the lock bolt; and a magnetically movable blocking means adapted for movement to a blocking position, preventing configuring of the solenoid to the opening configuration, or to a free position, allowing configuring of the solenoid to the opening configuration, wherein the blocking means is movable to the blocking position against its resilience, responsive to the application thereto of a magnetic force at or above the predetermined level, and is movable to the free position due to its inherent spring resilience, responsive to the application thereto of a magnetic force below the predetermined level. [0007] The blocking means is preferably adapted to move to the blocking position, responsive to the application thereto of a magnetic force at or above a predetermined level, and move to the free position responsive to the application thereto of a magnetic force below the predetermined level. [0008] The application of a magnetic force below the predetermined level includes the absence of a magnetic force. [0009] The solenoid preferably includes a plunger and a driver, and the blocking means prevents movement of the plunger in the blocking position and allows movement of the plunger in the free position. The hub preferably includes a recess and the plunger engages within the recess in the blocking position and is remote from the recess in the free position. [0010] The solenoid includes a protuberance that is abutted by the blocking means in the blocking position and that is remote from the blocking means in the free position. The protuberance is preferably a shoulder or flange, most preferably on the solenoid plunger. [0011] In one form, the blocking means is gravity biased towards the free position and driven to the blocking position responsive to the application thereto of a magnetic force at or above the predetermined level. In another form, the blocking means is spring biased towards the free position and is driven to the blocking position responsive to the application thereto of a magnetic force at or above the predetermined level.
3 [0012] In one embodiment, the blocking means is movable to the blocking position against the influence of gravity, responsive to the application thereto of a magnetic force at or above the predetermined level, and is movable to the free position under the influence of gravity, responsive to the application thereto of a magnetic force below the predetermined level. The blocking means is a ferrous metal, preferably steel, ball. The ball preferably rolls between the blocking position and the free position. [0013] [INTENTIONALLY LEFT BLANK] [0014] In a yet further embodiment, the blocking means is movable to the blocking position, responsive to the application thereto of a magnetic force at or above the predetermined level, and is adapted to stay in the blocking position after removal of the magnetic force at or above the predetermined level The blocking means is a ferrous metal, preferably steel, ball. The ball preferably rolls between the blocking position and the free position. Brief Description of the Drawings [0015] Preferred embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings in which: [0016] Fig. 1 is a schematic side view of a first embodiment of lock assembly in an opening configuration; [0017] Fig. 2 shows the lock assembly of Fig. 1 in a locking configuration; [0018] Fig. 3 shows the lock assembly of Fig. 2 during application of a magnetic force; [0019] Fig. 4 is a schematic side view of a second embodiment of a lock assembly in an opening configuration; [0020] Fig. 5 shows the lock assembly of Fig. 4 in a locking configuration; [0021] Fig. 6 shows the lock assembly of Fig. 5 during the application of a magnetic force; 4 [0022] Fig. 7 is a schematic perspective view of a third embodiment of lock assembly in an locking configuration; [0023] Fig. 8 shows the lock assembly of Fig. 7 during initial application of a magnetic force; [0024] Fig. 9 shows the lock assembly of Fig. 8 during further application of the magnetic force; and [0025] Fig. 10 shows the lock assembly of Fig. 9 after removal of the magnetic force. Detailed Description of the Preferred Embodiments [0026] Figs. I to 3 show a first embodiment of a lock assembly 10. The lock assembly 10 includes a lever type handle 12 which is operatively connected to a lock hub 14. More particularly, applying torque to the handle 12, so as to cause a pivoting movement, results in corresponding torque/pivotal movement in the hub 14. The hub 14 includes a plunger recess 14a. [0027] The lock assembly 10 also includes an electrically powered solenoid 16 which drives a plunger 18. The plunger 18 includes a peripheral flange 18a. The lock assembly 10 also includes a magnetically attractable blocking means, in the form of a steel ball 20, which is loosely located within a channel 22. The channel 22 slopes upwardly towards the plunger 18. [0028] The operation of the lock assembly 10 shall now be described. [0029] Fig. 1 shows the lock assembly 10 with the solenoid 16 retracted to an opening configuration in which the plunger 18 is retracted to a position where it does not engage into the plunger recess 14a of the hub 14. The ball 20 is positioned, under the influence of gravity, in the channel 22 in a free position remote from the plunger flange 18a. Accordingly, applying torque to the handle 12 results in it undergoing pivotal movement and causing corresponding pivotal movement in the hub 14. The lock assembly 10 is thus unlocked and an associated door can be opened. More particularly, the pivotal movement of the hub 14 is used to retract a lock bolt (not shown) for door opening. The lock bolt is not shown for reasons of drawing clarity but the construction and operation of lock bolts of this type are well known to persons skilled in the art and this aspect of the lock assembly operation is conventional.
5 [0030] Fig. 2 shows the lock assembly 10 after the solenoid 16 has been extended to a locking configuration, which extends the plunger 18 into, and in engagement with, the plunger recess 14a of the hub 14. This engagement prevents rotation of the hub 14. Accordingly, the application of torque to the handle 12 does not result in pivotal movement of the handle 12 nor of the hub 14 which could cause bolt retraction. As a result, the lock assembly 10 is locked and an associated door can not be opened by pivotal movement of the handle 12. The ball 20 remains in the free position under the influence of gravity. [0031] Fig. 3 shows the lock assembly 10 in the locking configuration described with reference to Fig. 2, with a magnet 24 applying an attracting force to the plunger 18. The attracting force of the magnet 24 also attracts the ball 20 and draws it to a blocking position adjacent to the plunger flange 18a. More particularly, the ball 20 is sandwiched between the underside of the plunger flange 18a and the top side of the adjacent end of the channel 22. When the ball is in this blocking position, movement of the plunger 18 away from the hub 14 is blocked or prevented. Accordingly, movement of the magnet 24 towards the solenoid 16 can not cause corresponding movement of the plunger 18. This advantageously makes the lock assembly 10 impervious to attempted opening by application of an external magnetic force. When the magnet 24 is removed, the ball 20 returns to the free position shown in Figs. 1 and 2 by rolling or sliding down the channel 22 under the influence of gravity. [0032] Figs. 4 to 6 show a second embodiment of lock assembly 30. The lock assembly 30 is similar to the lock assembly 10 previously described and like features are indicated with like reference numerals. However, in the lock assembly 30, the magnetically attractable blocking means is in the form of a steel cantilever beam 32 having a fixed proximal end 32a and a free distal end 32b. The fixed end 32a is secured to a housing part 34 of the lock assembly 30. [0033] The operation of the lock assembly 30 shall now be described. [0034] Fig. 4 shows the lock assembly 30 in an opening configuration, with the plunger 18 retracted, and the beam 32 in a free position. As a result, movement of the plunger 18 is not impeded by the beam 32. The lock assembly 30 is thus unlocked and an associated door can be opened by pivotal movement of the handle 12. [0035] Fig. 5 shows the lock assembly 30 in the locking configuration, after the solenoid 16 has been extended to extend the plunger 18 into engagement with the plunger recess 14a of the hub 6 14. The lock assembly 30 is thus locked and an associated door can not be opened by pivotal movement of the handle 12. [0036] Fig. 6 shows the lock assembly 30 in the locking configuration described with reference to Fig. 5, and after the application of a magnetic attracting force by the magnet 24. The attracting force causes the distal end 32b of the beam to flex to a blocking position adjacent the underside of the plunger flange 18a. When the beam 32 is in this blocking position, movement of the plunger 18 away from the hub 14 is blocked or prevented. As a result, movement of the magnet 24 towards the solenoid 16 is unable to draw the plunger 18 out of engagement with the plunger recess 14a in the hub 14. Again, this advantageously makes the lock assembly 30 impervious to attempted opening by application of an external magnetic force. When the magnet 24 is removed, the inherent spring resilience of the beam 32 returns it to the free position shown in Figs. 4 and 5. [0037] Figs. 7 to 10 show a third embodiment of lock assembly 50. The lock assembly 50 is similar to the lock assembly 10 previously described and like features are indicated with like reference numerals. However, in the lock assembly 50, the ball 20 is positioned to be able to interact directly with the hub 14. [0038] The operation of the lock assembly 50 shall now be described. [0039] Fig. 7 shows the lock assembly 50 with the solenoid 16 driving the plunger 18 to a locking configuration, with the plunger 18 extended into engagement with the plunger recess 14a of the hub 14. The lock assembly 30 is thus locked and an associated door can not be opened by pivotal movement of the handle 12. [0040] Fig. 8 shows the lock assembly 50 in the locking configuration described with reference to Fig. 7, and after the application of a magnetic attracting force by the magnet 24. The attracting force draws the ball 20 towards the distal end of the plunger 18 and the plunger recess 14a. [0041] Fig. 9 shows the lock assembly 50 after the magnetic attracting force of the magnet 24 has been used to draw the plunger 18 downwards and out of engagement with the plunger recess 14a in the hub 14. The magnetic attracting force of the magnet 24 also draws the ball 20 into the plunger recess 14a, where it prevents rotation of the hub 14. Accordingly, the application of 7 torque to the handle 12 does not result in pivotal movement of the handle 12 nor of the hub 14 which could cause bolt retraction. As a result, the lock assembly 10 is locked and an associated door can not be opened by pivotal movement of the handle 12. Again, this advantageously makes the lock assembly 50 impervious to attempted opening by application of an external magnetic force. [0042] Fig. 10 shows that when the magnet 24 is removed, the ball 20 remains in the blocking position due to the upward pressure exerted by the plunger 18. The ball 20 thus serves as an indicator of attempted magnetic lock opening. [0043] Although the invention has been described with reference to preferred embodiments, it will be appreciated by persons skilled in the art that the invention can be embodied in many other forms.