Abstract:
A lock assembly ( 20 ) including a lock bolt ( 28 ), a first hub ( 36 ) and a first hub locker ( 72 ). The lock bolt ( 28 ) is movable between a latching position and an unlatching position. The first hub ( 36 ) is adapted to move the lock bolt ( 28 ) in response to movement of a first handle. The first hub locker ( 72 ) is positionable in at least three positions. The first hub locker ( 72 ) allows movement of the lock bolt ( 28 ) in response to torque being applied to the first handle when in two of the at least three positions and prevents movement of the lock bolt in response to torque being applied to the first handle when in another of the at least three positions. Alternatively, the first hub locker ( 72 ) prevents movement of the lock bolt ( 28 ) in response to torque being applied to the first handle when in two of the at least three positions and allows movement of the lock bolt ( 28 ) in response to torque being applied to the first handle when in another of the at least three positions.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a lock assembly. 
     The invention has been developed primarily for use with an electrically controllable and electrically powered mortice lock and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular use and is also suitable for use in other types of locks, such as surface mounted locks. 
     BACKGROUND OF THE INVENTION 
     Electrically controllable and/or electrically powered locks are known. Such locks must be set to operate as either fail safe or fail secure. A fail safe lock automatically reverts to an unlocked state when its power supply is interrupted, for example during a power failure. A fail secure lock automatically reverts to a locked state when its power supply is interrupted. 
     Australian patent No. 657349 discloses an example of a known type of electrically controllable and powered mortice lock which can be set as fail safe or fail secure by adjusting components through openings in the side panels of the lock or after disassembly of the lock. The disadvantage of this arrangement is that the lock must be removed from the door in order to change the lock from fail safe to fail secure. 
     OBJECT OF THE INVENTION 
     It is the object of the present invention to substantially overcome or at least ameliorate the above disadvantage, and/or to provide an alternative. 
     SUMMARY OF THE INVENTION 
     Accordingly, in a first aspect, the present invention provides a lock assembly, the lock assembly including:
         a lock bolt movable between a latching position and an unlatching position;   a first hub adapted to move the lock bolt in response to movement of a first handle; and   a first hub locker positionable in at least three positions,       

     wherein the first hub locker allows movement of the lock bolt in response to torque being applied to the first handle when in two of the at least three positions and prevents movement of the lock bolt in response to torque being applied to the first handle when in another of the at least three positions or the first hub locker prevents movement of the lock bolt in response to torque being applied to the first handle when in two of the at least three positions and allows movement of the lock bolt in response to torque being applied to the first handle when in another of the at least three positions. 
     The first hub locker preferably allows movement of the lock bolt in response to torque being applied to the first handle when in two of the at least three positions and prevents movement of the lock bolt in response to torque being applied to the first handle when in another of the at least three positions or the first hub locker prevents movement of the lock bolt in response to torque being applied to the first handle when in said two of the at least three positions and allows movement of the lock bolt in response to torque being applied to the first handle when in said another of the at least three positions. 
     The first hub locker is preferably positionable in at least three positions and the first hub locker allows movement of the lock bolt in response to torque being applied to the first handle when in two of the three positions and prevents movement of the lock bolt in response to torque being applied to the first handle when in another of the three positions or the first hub locker prevents movement of the lock bolt in response to torque being applied to the first handle when in said two of the three positions and allows movement of the lock bolt in response to torque being applied to the first handle when in said another of the three positions. 
     In one form, the first hub locker allows movement of the lock bolt in response to torque being applied to the first handle when in two of the three positions and prevents movement of the lock bolt in response to torque being applied to the first handle when in another of the three positions. In another form, the first hub locker prevents movement of the lock bolt in response to torque being applied to the first handle when in said two of the three positions and allows movement of the lock bolt in response to torque being applied to the first handle when in said another of the three positions. 
     The first hub locker is preferably movable in a first direction from one of said two positions to said another position and from said another position to the other of said two positions. The first hub locker is preferably movable in a second direction, opposite to the first direction, from said other of said two positions to said another position and from said another position to said one of said two positions. 
     The lock assembly preferably includes a first driver, having an extended configuration and a retracted configuration, and a first adjustable mechanism, having an extended configuration and a retracted configuration, wherein:
         when the first driver is in the retracted configuration and the first adjustable mechanism is in the retracted configuration, the first hub locker is positioned in one of said two positions;   when the first driver is in the retracted configuration and the first adjustable mechanism is in the extended configuration, or the first driver is in the extended configuration and the first adjustable mechanism is in the retracted configuration, the first hub locker is positioned in said another position; and   when the first driver is in the extended configuration and the first adjustable mechanism is in the extended configuration, the first hub locker is positioned in the other of said two positions.       

     In one form, the lock assembly preferably includes a first driver, drivable to a retracted configuration and biased to an extended configuration, and a first adjustable mechanism, settable in an extended configuration or a retracted configuration. In another form, the lock assembly preferably includes a first driver, drivable to an extended configuration and biased to a retracted configuration, and a first adjustable mechanism, settable in an extended configuration or a retracted configuration. 
     The first adjustable mechanism is preferably a first length adjustable mechanism, having a relatively longer length in the extended configuration and a relatively shorter length in the retracted configuration. 
     The lock assembly preferably also includes:
         a second hub adapted to move the lock bolt in response to movement of a second handle; and   a second hub locker positionable in at least three positions,       

     wherein the second hub locker allows movement of the lock bolt in response to torque being applied to the second handle when in two of the at least three positions and prevents movement of the lock bolt in response to torque being applied to the second handle when in another of the at least three positions or the second hub locker prevents movement of the lock bolt in response to torque being applied to the second handle when in two of the at least three positions and allows movement of the lock bolt in response to torque being applied to the second handle when in another of the at least three positions. 
     The second hub locker preferably allows movement of the lock bolt in response to torque being applied to the second handle when in two of the at least three positions and prevents movement of the lock bolt in response to torque being applied to the second handle when in another of the at least three positions or the second hub locker prevents movement of the lock bolt in response to torque being applied to the second handle when in said two of the at least three positions and allows movement of the lock bolt in response to torque being applied to the second handle when in said another of the at least three positions. 
     The second hub locker is preferably positionable in three positions and the second hub locker allows movement of the lock bolt in response to torque being applied to the second handle when in two of the three positions and prevents movement of the lock bolt in response to torque being applied to the second handle when in another of the three positions or the second hub locker prevents movement of the lock bolt in response to torque being applied to the second handle when in said two of the three positions and allows movement of the lock bolt in response to torque being applied to the second handle when in said another of the three positions. 
     In one form, the second hub locker allows movement of the lock bolt in response to torque being applied to the second handle when in two of the three positions and prevents movement of the lock bolt in response to torque being applied to the second handle when in another of the three positions. In another form, the second hub locker prevents movement of the lock bolt in response to torque being applied to the second handle when in said two of the three positions and allows movement of the lock bolt in response to torque being applied to the second handle when in said another of the three positions. 
     The second hub locker is preferably movable in a first direction from one of said two positions to said another position and from said another position to the other of said two positions. The second hub locker is preferably movable in a second direction, opposite to the first direction, from said other of said two positions to said another position and from said another position to said one of said two positions. 
     The lock assembly preferably includes a second driver, having an extended configuration and a retracted configuration, and a second adjustable mechanism, having an extended configuration and a retracted configuration, wherein:
         when the second driver is in the retracted configuration and the second adjustable mechanism is in the retracted configuration, the second hub locker is positioned in one of said two positions;   when the second driver is in the retracted configuration and the second adjustable mechanism is in the extended configuration, or the second driver is in the extended configuration and the second adjustable mechanism is in the retracted configuration, the second hub locker is positioned in said another position; and   when the second driver is in the extended configuration and the second adjustable mechanism is in the extended configuration, the second hub locker is positioned in the other of said two positions.       

     In one form, the lock assembly preferably includes a second driver, drivable to a refracted configuration and biased to an extended configuration, and a second adjustable mechanism, settable in an extended configuration or a retracted configuration. In another form, the lock assembly preferably includes a second driver, drivable to an extended configuration and biased to a retracted configuration, and a second adjustable mechanism, settable in an extended configuration or a retracted configuration. 
     The second adjustable mechanism is preferably a second length adjustable mechanism, having a relatively longer length in the extended configuration and a relatively shorter length in the retracted configuration. 
     In a second aspect, the present invention provides a lock assembly, the lock assembly including:
         a housing adapted for installation on or in a door;   a lock bolt movable between a latching position and an unlatching position;   a first hub adapted to move the lock bolt in response to movement of a first handle; and   a first hub locker assembly settable for fail safe operation or fail secure operation whilst the housing is installed on or in the door.       

     In a third aspect, the present invention provides a lock assembly, the lock assembly including:
         a housing adapted for installation on or in a door;   a lock bolt movable between a latching position and an unlatching position;   a first hub adapted to move the lock bolt in response to movement of a first handle; and   a first hub locker assembly settable for fail safe operation or fail secure operation without removing the housing from on or in the door.       

     The housing preferably includes a front face, installed substantially adjacent the free edge of the door, and the first hub locker assembly is settable for fail safe operation or fail secure operation via access means in the front face of the housing. 
     The first hub locker assembly preferably includes a first driver, having an extended configuration and a retracted configuration, and a first length adjustable mechanism, settable in an extended configuration or a retracted configuration via the access means. 
     The first hub locker is preferably positionable in at least three positions, wherein the first hub locker allows movement of the lock bolt in response to torque being applied to the first handle when in two of the at least three positions and prevents movement of the lock bolt in response to torque being applied to the first handle when in another of the at least three positions or the first hub locker prevents movement of the lock bolt in response to torque being applied to the first handle when in two of the at least three positions and allows movement of the lock bolt in response to torque being applied to the first handle when in another of the at least three positions. 
     The lock assembly preferably includes:
         a second hub adapted to move the lock bolt in response to movement of a second handle; and   a second hub locker assembly settable for fail safe operation or fail secure operation whilst the housing is installed on or in the door.       

     The lock assembly preferably includes:
         a second hub adapted to move the lock bolt in response to movement of a second handle; and   a second hub locker assembly settable for fail safe operation or fail secure operation without removing the housing from on or in the door.       

     The housing preferably includes a front face, installed substantially adjacent the free edge of the door, and the second hub locker assembly is settable for fail safe operation or fail secure operation via access means in the front face of the housing. 
     The first hub locker assembly preferably includes a second driver, having an extended configuration and a retracted configuration, and a second length adjustable mechanism, settable in an extended configuration or a retracted configuration via the access means. 
     The second hub locker is preferably positionable in at least three positions, wherein the second hub locker allows movement of the lock bolt in response to torque being applied to the second handle when in two of the at least three positions and prevents movement of the lock bolt in response to torque being applied to the second handle when in another of the at least three positions or the second hub locker prevents movement of the lock bolt in response to torque being applied to the second handle when in two of the at least three positions and allows movement of the lock bolt in response to torque being applied to the second handle when in another of the at least three positions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying drawings wherein: 
         FIG. 1  is a perspective view of a first embodiment of the lock assembly; 
         FIG. 2 a    is a perspective view of the lock assembly shown in  FIG. 1  with the side cover removed, set to fail safe and not energised/unlocked; 
         FIG. 2 b    is an exploded perspective view of the lock assembly shown in  FIG. 2   a;    
         FIG. 3  shows the lock assembly of  FIG. 2 a    with a hub rotated and bolts retracted; 
         FIG. 4  shows the lock assembly of  FIG. 2 a    set to fail safe and energised/locked; 
         FIG. 5  shows the lock assembly of  FIG. 4  with additional parts to provide for bolt retraction via key override; 
         FIG. 6  shows the lock assembly of  FIG. 5  with bolts retracted via key override; 
         FIG. 7  shows the lock assembly of  FIG. 2 a    with a face plate removed and a cylinder pin positioned for use in setting to fail secure; 
         FIG. 8  shows the lock assembly of  FIG. 7  set to fail secure and not energised/locked; 
         FIG. 9  shows the lock assembly of  FIG. 8  set to fail secure and energised/unlocked; 
         FIG. 10  shows the lock assembly of  FIG. 8  with the face plate removed and the cylinder pin positioned for use in setting to fail safe; 
         FIG. 11  is a perspective view of a second embodiment of lock assembly and a cylinder pin positioned for use in setting to fail secure; 
         FIG. 12  shows the lock assembly shown in  FIG. 11  and a cylinder pin positioned for use in setting to fail safe; 
         FIG. 13 a    is a perspective view of an length adjustable mechanism in a retracted configuration; 
         FIG. 13 b    is an exploded perspective view of the adjuster shown in  FIG. 13   a;    
         FIG. 13 c    is a cross sectional side view of the adjuster shown in  FIG. 13   a;    
         FIG. 14 a    is a perspective view of the adjuster shown in  FIG. 13 a    in an extended configuration; 
         FIG. 14 b    is a cross sectional side view of the adjuster shown in  14   a;    
         FIG. 15  is a perspective view of a third embodiment of lock assembly with a side cover removed, set to fail secure and not energised/locked; 
         FIG. 16  shows the lock assembly of  FIG. 15  set to fail secure and energised/unlocked; 
         FIG. 17  shows the lock assembly of  FIG. 16  with a hub rotated and bolts withdrawn; 
         FIG. 18  shows the lock assembly of  FIG. 15  set to fail safe and not energised/unlocked; and 
         FIG. 19  shows the lock assembly of  FIG. 18  set to fail safe and energised/locked. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows an embodiment of an electrically controllable and electrically powered mortice lock assembly  20 . The lock assembly  20  includes a housing  22  with a side cover  24  and a face plate  26 . The lock assembly  20  is installed in a door with the housing  22  within a mortice void in the door and the face plate  26  adjacent to the non-hinged edge of the door, as is well understood by persons skilled in the art. A latch bolt  28  and an auxiliary bolt  30  pass through the faceplate  26  for engagement with a strike plate (not shown) in a door jamb, as is also well understood by persons skilled in the art. The side of the lock assembly  20  shown in  FIG. 1  will be referred to as the first side and the opposite side as the second side. 
     The lock assembly  20  also includes an opening  32  that receives a key cylinder assembly (not shown) therein. The key cylinder assembly is retained within the opening  32  with a key cylinder retaining pin  34  (see  FIG. 7 ), as is also well understood by persons skilled in the art. After the key cylinder assembly has been inserted into the opening  32 , and the key cylinder retaining pin  34  inserted into the key cylinder assembly, the key cylinder retaining pin  34  is prevented from releasing its engagement with the key cylinder assembly by engagement of the faceplate  26  with the housing  22 . 
     The lock assembly  20  also includes a first hub  36  with a square cross section opening  38  therein, which is adapted to engage with a square cross section drive shaft (not shown) of a first external knob, lever or other handle (not shown). 
       FIG. 2 a    shows the lock assembly  20  with the side cover  24  of the housing  22  removed. The latch bolt  28  is connected to a latch bolt shaft  46  which is in turn connected to a latch bolt carriage  48 . The auxiliary bolt  30  is connected to an auxiliary bolt shaft  50  which is in turn connected to an auxiliary bolt carriage  52 . The latch bolt  28  and the auxiliary bolt  30  are biased toward a latching position, as shown in  FIG. 2 a   , by a latch spring  54  and an auxiliary latch spring  56  respectively. 
     A carriage retraction arm  58  is pivotally mounted to the housing  22  by a shaft  60  and biased toward the position shown in  FIG. 2 a    by a spring  62 . The arm  58  can be moved to retract the latch bolt  28  and the auxiliary bolt  30  under certain conditions, in response to movement of the first or second handles or the key cylinder assembly, as will be described in more detail below. 
       FIG. 2 a    also shows a first electrically powered hub locker assembly comprising a first electrically powered solenoid  64  which is connected to a first length adjustable mechanism  66  which is in turn connected to a first link  68  which is in turn connected to a first lever  70  which is in turn connected to a first hub locking part  72 . The first lever  70  pivots about a first boss  74 . The first solenoid  64  is of the pull type and also includes a first biasing spring  76 . 
     As best shown in  FIG. 2 b   , the lock assembly  20  also includes a second handle, a second hub  36 ′ and a second electrically powered hub locker assembly on its opposite side. The second electrically powered hub lock assembly comprises a second electrically powered solenoid  64 ′ which is connected to a second length adjustable mechanism  66 ′ which is in turn connected to a second link  68 ′ which is in turn connected to a second lever  70 ′ which is in turn connected to a second hub locking part  72 ′. The second electrically powered solenoid  64 ′ is also a pull type and includes a second biasing spring  76 ′. 
       FIG. 2 a    also shows a first hub locking sensor  78  which is able to provide a signal indicative of the position of the first electrically powered hub locker assembly to allow remote signalling of the lock status of the first hub  36  to a remotely located controller or other internal control.  FIG. 2 b    shows a similar sensor  78 ′ provided for the second hub locker assembly.  FIG. 2 a    also shows a latch bolt sensor  82  and an auxiliary bolt sensor  84 , which similarly signal the position of the latch bolt  28  and the auxiliary bolt  30  respectively. Other sensors (not shown) can also be added as desired to other mechanical facets of the lock assembly  20  and/or to remotely signal lock and/or door status or to provide other internal control. 
       FIG. 2 b    also shows that the first hub  36  has a flange  80  carrying a protruding part  82 . An identical flange  80 ′ and protruding part  82 ′ are present on the second hub  36 ′. The first hub locking part  72  also includes a protruding part  84 . An identical protruding part  84 ′ is provided on the second hub locking part  72 ′. 
       FIGS. 13 a  to 14 b    show the first length adjustable mechanism  66 . The second length adjustable mechanism  66 ′ is identical to the first.  FIG. 13 b    shows the component parts of the first length adjustable mechanism  66 , namely a first housing part  90 , a second housing part  92 , a spring  94 , a spring cup  96  and a connector  98 . The first length adjustable mechanism  66  is settable in either a relatively shorter ‘retracted’ configuration, as shown in  FIGS. 13 a  and 13 c   , or a relatively longer ‘extended’, configuration as shown in  FIGS. 14 a  and 14 b   . In either configuration, the spring  94  continually urges the cup  96  and thus the connector  98  in the direction indicated by arrow A. 
     When the mechanism  66  is in the retracted configuration shown in  FIG. 13 c    the spring  94  maintains the proximal end of the connector  98  in engagement with the first housing part. When force is applied to the proximal end of the connector  98 , in the direction of arrow B, then the proximal end of the connector  98  is released from engagement with the first housing part  90  and the connector  98  is propelled by the spring  94  to the extended configuration shown in  FIG. 14 b   . When the mechanism  66  is in the extended configuration shown in  FIG. 14 b   , then applying force in the direction of arrow C to the distal end of the connector  98  compresses the spring  94  and also causes the connector  98  to pivot, due to the interaction of its curved proximal end against the spring cup  96 , until it reaches the retracted configuration shown in  FIG. 13 c   . As mentioned above, when the mechanism is in the retracted configuration shown in  FIG. 13 c   , the spring  94  maintains the proximal end of the connector  98  in engagement with the first housing part  90 . 
     In summary, applying force in the direction and position of the arrow B changes the mechanism  66  from the retracted configuration to the extended configuration and applying force in the direction and position of the arrow C changes the mechanism  66  from the extended configuration to the refracted configuration. 
     Returning to  FIG. 2 a   , the first solenoid  64  also has an extended configuration as shown in  FIG. 2 a    and a retracted configuration as shown in  FIG. 4 . As previously mentioned, the first solenoid  64  is of the pull type and when energized its distal end is pulled to the retracted configuration against the bias of the spring  76 . When the solenoid is not energized the spring  76  drives the distal end of the first solenoid  64  to the extended configuration. 
     The operation of the lock assembly  20  shall now be described.  FIG. 2 a    shows the lock assembly  20  set to a fail safe configuration by the setting of the first length adjustable mechanism  66  set in the extended configuration. The first solenoid  64  is shown not energized and thus in the extended configuration. As a result, the first link  68  and the first lever  70  are positioned to place the first hub locking part  72  into what shall be referred to as a first position, relatively close to the first hub  36 . In this first position, the protruding part  82  is not aligned with the protruding part  84  and if torque is applied to the first hub  36  the first hub  36  can pivot as the protruding part  82  passes the protruding part  84 . The first hub  36  has a first shoulder  36   a  which bears against a protuberance  58   a  on the carriage retraction arm  58  to cause the carriage retraction arm  58  to pivot in response to pivoting of the first hub  36 . As shown in  FIG. 3 , the pivoting of the carriage retraction arm  58 , in response to the pivoting of the first hub  36 , withdraws the lock bolt  28  and the auxiliary bolt  30 , allowing the door to be opened. 
       FIG. 4  shows the lock assembly set to a fail safe configuration (i.e. the first length adjustable mechanism  66  set in the extended configuration) but with the first solenoid energized and thus in the retracted configuration. As a result, the first link  68  and the first lever  70  are positioned to place the first hub locking part  72  into what shall be referred to as a second position, further away from the first hub  36  than in the first position. In the second position, the protruding part  82  is in alignment with the protruding part  84 . Accordingly, when torque is applied to the first hub  36  it is unable to pivot as the protruding part  82  abuts the protruding part  84 . This locks the first side of the lock assembly  20 . 
     In summary, when the first length adjustable mechanism  66  is in the extended configuration the first side of the lock assembly  20  is set as fail safe and de-energising the first solenoid  64  drives the first locking part  72  to the first position, unlocking the first side of the lock assembly  20 , and energising the first solenoid  64  drives the first locking part  72  to the second position, locking the first side of the lock assembly  20 . 
       FIG. 5  shows the lock assembly  20  in the same fail safe and locked configuration as  FIG. 3  and also shows a key cylinder retraction bar  90 . The key cylinder retraction bar  90  has a first end  92  connected to the carriage retraction arm  58  and a second end with a depending part  94 .  FIG. 6  shows the lock assembly  20  of  FIG. 5  after the depending part  106  has been driven in a direction away from the first hub  36  by rotation of the key cylinder assembly (not shown) by a correct key. The resulting movement in the key cylinder retraction bar  90  pivots the carriage retraction arm  58  to withdraw the lock bolt  28  and the auxiliary bolt  30 . It will be appreciated that this action, known as key override unlatching, withdraws the bolts  28  and  30  for door opening but does not unlock the lock assembly  20 . Accordingly, as soon as torque is removed from the key used to pivot the key cylinder assembly, the springs  54  and  56  extend the bolts  28  and  30  respectively and return the lock assembly  20  to the locked configuration shown in  FIG. 5 . 
       FIG. 7  shows the lock assembly  20  with the face plate  26  removed. This provides access to a first fail secure adjuster setting hole  102 , a first fail safe adjuster setting hole  104 , a second fail secure adjuster setting hole  106  and a second fail safe adjuster setting hole  108 . Each of the holes  102 ,  104 ,  106  and  108  have a respective hollow guide  110 ,  112 ,  114  and  116  in the interior of the housing  22 . To change the setting of the first side of the lock assembly  20  from fail safe to fail secure, the key cylinder retaining pin  34  is inserted into the first fail secure adjuster setting hole  102  until it presses against the region  70   a  of the first lever  70 . Applying force to the key cylinder retaining pin  34  then causes the first lever  70  to pivot in a counter clockwise direction, which drives the link  68  towards the first length adjustable mechanism  66 . The first link  68  then drives the distal end of the connector  98  to compress the spring  94  and causes the connector  98  to pivot, due to the interaction of its curved proximal end against the spring cup  96 , until it reaches the retracted configuration. This is the same as the movement described in relation to the arrow C with reference to  FIGS. 13 a    to  14   b.    
       FIG. 8  shows the lock assembly  20  set to a fail secure configuration (i.e. the first length adjustable mechanism  66  set in the retracted configuration) after the process described with reference to  FIG. 7 . The first solenoid  64  is shown not energized and thus in the extended configuration. As a result, the first link  68  and the first lever  70  are positioned to place the first hub locking part  72  into the previously described second position. In the second position, the protruding part  82  is in alignment with the protruding part  84 . Accordingly, when torque is applied to the first hub  36  it is unable to pivot as the protruding part  82  abuts the protruding part  84 , thus locking the first side of the lock assembly  20 . 
       FIG. 9  shows the lock assembly set to the fail secure configuration shown in  FIG. 8  but with the first solenoid energized and thus in the retracted configuration. As a result, the first link  68  and the first lever  70  are positioned to place the first hub locking part  72  into what shall be referred to as a third position, further away from the first hub  36  than in the second position. In the third position, the protruding part  82  is not in alignment with the protruding part  84 . Accordingly, when torque is applied to the first hub  36  the first hub  36  can pivot as the protruding part  82  passes the protruding part  84 . The pivoting of the carriage retraction arm  58 , in response to the pivoting of the first hub  36 , withdraws the lock bolt  28  and the auxiliary bolt  30 , as shown in  FIG. 3 . 
     In summary, when the first length adjustable mechanism  66  is in the retracted configuration the first side of the lock assembly  20  is set as fail secure and de-energising the first solenoid  64  drives the first locking part  72  to the second position, locking the first side of the lock assembly  20 , and energising the first solenoid  64  drives the first locking part  72  to the third position, unlocking the first side of the lock assembly  20 . 
     With reference to  FIG. 10 , to change the first side of the lock assembly  20  from fail secure to fail safe, the key cylinder retaining pin  34  is inserted into the first fail safe adjuster setting hole  104  until it presses against the proximal end of the connector  98  in the first length adjustable mechanism  66 . When force is applied to the proximal end of the connector  98 , the proximal end of the connector  98  is released from engagement with the first housing part  90  and the connector  98  is propelled by the spring  94  to the extended configuration. This is the same as the movement described in relation to the arrow B with reference to  FIGS. 13 a  to 14 b   . When the first length adjustable mechanism  66  is in the extended configuration the first side of the lock is set as fail safe as previously described with reference to  FIGS. 3 and 4 . 
     The second side of the lock assembly  20  operates in the same manner as described in relation to the first side. The setting of the second side as fail safe or fail secure is performed using the key cylinder pin  34  in the second fail secure adjuster setting hole  106  or the second fail safe adjuster setting hole  108 , and is independent of the setting of the first side and vice versa. 
     The lock assembly  20  can be set as fail safe or fail secure before installation in a door. The lock assembly  20  can also be set as fail safe or fail secure after installation in a door by removal of the face plate  26  only and, advantageously, without having to disassemble the entire lock assembly  20 . This greatly reduces the effort and expense of changing the lock&#39;s setting after installation if: the initial setting was incorrectly made at installation; or a change in the door&#39;s function is required due to a subsequent building or security requirement change. 
       FIGS. 11 and 12  shows a second embodiment of lock assembly  120 . The lock assembly  120  is similar to the lock assembly  20  and like features are indicated with like reference numerals. However, the lock assembly  120  does not include the first fail secure adjuster setting hole  102 , the first fail safe adjuster setting hole  104 , the second fail secure adjuster setting hole  106  or the second fail safe adjuster setting hole  108  beneath the face plate. As an alternative, the lock assembly  120  has a first fail secure adjuster setting hole  122  and a first fail safe adjuster setting hole  124  in the side cover  24  and a second fail secure adjuster setting hole and a second fail safe adjuster setting hole on the second (i.e. opposite) side of the housing  22 . 
     As shown in  FIG. 7 , to change the setting of the first side of the lock assembly  20  from fail safe to fail secure, the key cylinder retaining pin  34  is inserted into the first fail secure adjuster setting hole  122  until it presses against the region  70   a  of the first lever  70  and moved laterally to cause the first lever  70  to pivot in a counter clockwise direction and drive the link  68  towards the first length adjustable mechanism  66 . The first link  68  then drives the distal end of the connector  98  to compress the spring  94  and causes the connector  98  to pivot, due to the interaction of its curved proximal end against the spring cup  96 , until it reaches the retracted configuration. This is the same as the movement described in relation to the arrow C with reference to  FIGS. 13 a    to  14   b.    
     With reference to  FIG. 12 , to change the setting of the first side of the lock assembly  20  from fail secure to fail safe, the key cylinder retaining pin  34  is inserted into the first fail safe adjuster setting hole  124  until it presses against the proximal end of the connector  98 . The pin  34  is them moved laterally to apply force to the proximal end of the connector  98 . This releases the proximal end of the connector  98  from engagement with the first housing part  90  and allows the connector  98  to be propelled by the spring  94  to the extended configuration. This is the same as the movement described in relation to the arrow B with reference to  FIGS. 13 a    to  14   b.    
     The lock assembly  120  can only be set as fail safe or fail secure before installation in a door or after removal of the lock assembly  120  from a door. The lock assembly  120  may be suited to more secure applications as the settings can not be tampered with without removing the lock assembly from the door. 
       FIGS. 15 to 19  show a third embodiment of lock assembly  140 . The lock assembly  140  is also similar to the lock assembly  20  and like features are indicated with like reference numerals. However, in the lock assembly  140  the hub  36  has an inner protruding part  142  and an outer protruding part  144  separated by a slot  146  and the first hub locking part  72  has a protruding part  148  adjacent its distal end. 
     The operation of the lock assembly  140  is similar but reversed to that previously described in relation to the lock assembly  20 . As shown in  FIG. 15 , when the first length adjustable mechanism  66  is in the extended configuration the first side of the lock assembly  140  is set as fail secure. De-energising the first solenoid  64  drives the first locking part  72  to the first position, locking the first side of the lock assembly  140 . As shown in  FIG. 16 , energising the first solenoid  64  drives the first locking part  72  to the second position, unlocking the first side of the lock assembly  140 . As shown in  FIG. 17 , the bolts  28  and  30  can then be retracted. 
     As shown in  FIG. 18 , when the first length adjustable mechanism  66  is in the retracted configuration the first side of the lock assembly  140  is set as fail safe. De-energising the first solenoid  64  drives the first locking part  72  to the second position, unlocking the first side of the lock assembly  20 . As shown in  FIG. 19 , energising the first solenoid  64  drives the first locking part  72  to the third position, locking the first side of the lock assembly  140 . 
     By way of a comparison, the lock assembly  20  allows rotation of the hub when the hub locking part is in the first and third positions and prevents it when in the second position. The lock assembly  140  prevents rotation of the hub when the hub locking part is in the first and third positions and allows it when in the second position. 
     The lock assembly  140  can be set as fail safe or fail secure before installation in a door. The lock assembly  140  can also be set as fail safe or fail secure after installation in a door by removal of the face plate  26  only and, advantageously, without having to disassemble the entire lock assembly  140 . 
     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. For example, in the embodiments shown, the change in length of the length adjustable mechanisms between their retracted and extended configurations is approximately the same as the change in length of the solenoids between their retracted and extended configurations. However, in other embodiments (not shown) these two length changes are not the same. Also, the described embodiments show the hub locking parts moving between only three positions. However, in other embodiments (not shown) more than three positions are utilised.