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CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a Continuation of U.S. application Ser. No. 10/536,615, filed May 26, 2005, which is the National Stage of International Application No. PCT/AU03/01596, filed Dec. 1, 2003, which claims the benefit of Australian Application Serial No. AU 2002953027, filed Nov. 29, 2002; and is a Continuation-in-Part of U.S. application Ser. No. 10/276,547, filed Nov. 14, 2002 and now U.S. Pat. No. 6,964,183, which is the National Stage of International Application No. PCT/AU01/00579, filed May 18, 2001, which claims the benefit of Australian Application No. PQ7576, filed May 18, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a dual lock apparatus, and in particular, to a dual lock apparatus that has at least two independent means of acting on a lock whereby operation of the two locking means is controlled by an improved clutch mechanism. 
     2. Background Information 
     In a previous patent by the same applicant (PCT/AU01/00579 entitled ‘A Dual Lock Apparatus’), whose contents are expressly incorporated by reference herein, there was disclosed a locking apparatus having at least two independent means of acting on a lock. Although the apparatus as described in the aforementioned patent has been found to function satisfactorily, an improved clutch mechanism which allows the two locking mechanisms to function independently has been developed and is the subject of the present application. 
     There are numerous types of locks in existence today that are used to secure various devices. One of the more common uses of locks is in relation to doors. Typically door locks have a bolt that can be extended from a locking mechanism so as to engage a doorframe or furniture with the bolts being driven by the use of a unique or slave key. There have also been developed locks that are not only operable by the use of the slave key but also a master key, allowing the master key holder, for example, to operate all doors in a pre-defined area whilst the slave key holders are limited to being able to operate specific doors only. This however requires the master key and the slave key to be of the same type thus potentially compromising security. 
     There have also been developed electromechanical locks that use an electric motor to drive the bolt. The difficulty with these types of arrangements is that if the electric motor was for whatever reason inoperable, the door may be left either in the unlocked or locked state and may require disassembly to be fixed. 
     Further still, the difficulty with some existing locks is that although the door may be unlocked, that is it may be opened, the bolt still engages a portion of the door frame and further manual operation of the bolt by the use of a handle is required to be able to open the door. On the other hand, if the bolt was to be retracted fully, then the door may swing freely, also an undesirable effect. 
     It is an object of the present invention to propose a locking apparatus that overcomes at least some of the abovementioned problems or provides the public with a useful alternative. 
     Although the present specification discusses doors in particular it is to be understood that the present invention is not intended to be limited to doors and may equally well be used to provide a locking apparatus in relation to other devices such as safes and gates to name but two. 
     SUMMARY OF THE INVENTION 
     In one form of the invention there is proposed a dual lock apparatus of the type including a lock moveable between a first position whereby said lock extends outwardly from said apparatus and a second position whereby said lock is contained within said apparatus said apparatus including: 
     a slider movable between a first position and a second position and including a first end associated with said lock such that movement of the slider causes corresponding movement of the lock, and a second end associated with a first locking means and a second locking means whereby independent operation of said first and second locking means is controlled by a clutch mechanism; 
     said clutch mechanism including an aperture which extends through said slider and a piston movable between at least a first and second position within said slider aperture; 
     said second locking means including a member movable between a first and a second position said member including an outwardly biased locking member adapted to engage said slider aperture to thereby mechanically connect said second locking means with said slider to thereby effect movement of said slider upon movement of said member; 
     said first locking means including a rotatable cam such that when rotated said cam acts against said piston to thereby move said piston from said first position to said second position to thereby mechanically connect said first locking means with said slider to thereby effect movement of said slider. 
     Preferably said first locking means disengages said second locking means. 
     This allows independent operation of said first locking means with respect to said second locking means. 
     The above provides the advantage that if the second locking means is one that may be exposed to potential failure, the first locking means ensures that there is a safeguard in that the lock can always be operated even if the secondary locking means has ceased to function. 
     Advantageously at least one of said locking means is electrically driven. Advantageously said first locking means is a key activated locking means whilst said second locking means is an electromechanical locking means. 
     Preferably both said first and second locking means are key activated. 
     A particularly apt use of this invention is in the case where the electromechanical locking means is controlled by remote activation of an electric motor. If for whatever reason the electric motor were to fail, such as a power failure, then the primary locking mechanism that is operated for example by a key may be used to unlock or lock the lock. 
     Advantageously when said slider interacts with said locking bolt so as to move it into said first position, said slider resists withdrawal of said locking bolt. 
     In a further form of the invention there is proposed a dual lock apparatus of the type including a locking bolt moveable between a first position extending outwardly from said apparatus to engage with an external restraining means and a second position to be contained within said casing said apparatus including: 
     a slider adapted to interact with said locking bolt so as to move it into said first or second position said slider including at one end an aperture extending perpendicularly to the direction of motion of said slider said aperture adapted to house a slider abutment member; 
     said slider abutment member being moveable between a first position whereby a surface of said member is flush with a surface of said slider and a second position whereby said surface of said member is housed within said aperture; 
     a carriage associated with said slider said carriage including an abutment surface said carriage further being moveable between a first position wherein said slider is located in said slider second position, and a second position thereby urging said slider into said slider first position; 
     a first locking means having a rotatable cam means such that when rotated in a first direction so as to act against said carriage abutment surface urges said carriage into said carriage second position and said abutment member into said first position to thereby urge the slider towards its first position and thereby outwardly extend said bolt and when said cam is rotated in an opposite direction it acts to thereby urge the slider towards its second position to thereby inwardly retract said bolt; 
     a second locking means adapted to be activated independent of said first locking means including a rack associated with said slider and movable between a first position whereby said bolt is inwardly retracted and a second position whereby said bolt is outwardly extended, said member including an outwardly biased pin housed within a rack cavity and movable between a first and a second position, in said first position said pin engaging with said slider aperture to thereby effectively mechanically couple said second locking means to said slider and thus the bolt and in said second position said pin forced into said cavity whereby said slider may freely move to thereby effectively decouple said second locking means from the slider, this occurring when said slider abutment member is in said member first position. 
     Preferably when said cam discontinues urging of said carriage, a biasing member acts upon said pin to return it to said first position upon alignment of said pin and said slider aperture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several implementations or embodiments of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings, 
         FIG. 1  is a top view of the internal components of a lock in an unlocked configuration and including the lock slider body of the present invention; 
         FIG. 2  is a top view of the internal components of the lock of  FIG. 1  in a locked configuration using a secondary locking mechanism, more specifically, an electric motor and rack system; 
         FIG. 3  is an exploded perspective view of the different components of the lock of  FIG. 1 ; 
         FIG. 4  is an alternate exploded perspective view of the different components of the lock of  FIG. 1 ; 
         FIG. 5  is a cross-sectional view of the main component of the lock of  FIG. 1  whereby the secondary locking mechanism is used to lock the bolt; 
         FIG. 6  is a cross-sectional view of the main component of the lock of  FIG. 1  whereby a primary locking mechanism (a key operated cam) disengages the secondary locking mechanism; 
         FIG. 7  is a cross-sectional view of the lock as in  FIG. 6  whereby the primary locking mechanism is used to lock the bolt subsequent to disengagement of the secondary locking mechanism; 
         FIG. 8  is a cross-sectional view of the main components of the lock of  FIG. 1  whereby the lock is in its fully locked state using the primary locking mechanism; and 
         FIG. 9  is a cross-sectional view of the main components of the lock of  FIG. 1  whereby the lock is in its fully unlocked state using the primary locking mechanism. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following detailed description of the invention refers to the accompanying drawings. Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described without departing from the spirit and scope of the invention. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. 
     The present invention relates to locks and in particular to locks that are used for hollow winged aluminium doors and the like. It may also be adapted to be used on other type of doors such as sliding doors. It is not intended to limit the invention to any particular type of lock or door. 
     Shown in  FIGS. 1 and 2  is a dual lock  10  in accordance with the present invention,  FIG. 1  illustrating the lock  10  in its unlocked state and  FIG. 2  showing the lock  10  in its locked state.  FIGS. 1 and 2  illustrate the use of a secondary locking mechanism, generally indicated at  99 , that is, the use of an electric motor  100  to lock or unlock the lock  10  and which will be described hereinbelow. The primary locking mechanism, which is slightly more complex, will also be described. 
     A casing  12  is adapted to slidingly support a locking bolt  14  said bolt  14  being biased outwardly from said casing  12  by the use of a spring (not shown). The bolt  14  includes a sunken shoulder  16  at one side of the bolt rear end, said shoulder supporting an annular projection  18 . The bolt  14  is adapted to slide generally in a perpendicular axis  20  to the longitudinal axis  22  of the casing  12 . A lock case  24  limits the outward movement of said bolt. 
     A slider  26  is adapted to slide along the longitudinal direction  22  within the casing  12  and includes a first longitudinal slit  28  engaging a screw  30 , the screw  30  providing holding support for the lock  10 . 
     The slider  26  includes a second slit  32  extending at an inclined direction to both the perpendicular and the longitudinal axis  20  and  22  respectively. Slit  32  engages projection  18  of the shoulder  16 . One can thus appreciate that when the slider is moved towards the bolt, the inclination of the slit  32  causes the bolt  14  to be extended outwardly from said casing  12 . Conversely, when the slider  26  is moved in a direction away from the bolt  14 , the slit  32  acting on the shoulder projection  18  urges the bolt  14  to be withdrawn into the casing  12 . When locked, the slider  26  is maintained through use of a biasing member  34 , which may be indexed with a recess in the lid (not shown), for example. 
     The slider  26  may further include a shoulder  36  adapted to abut against face  38  in the casing  12  to act as a dead stop for the slider motion. 
     The end of the slit  32  where the bolt is caused to extend out of said casing includes a hooked portion  40  where the slit extends in a longitudinal direction parallel to the casing and thus perpendicular to the movement of the bolt. This has the advantage that when the projection  18  is located within the hooked location  40 , the slider effectively deadbolts the bolt. That is, if the bolt experiences an inward force, the edge  42  of the hooked portion  40  of the slit  32  engages the projection  18  and prevents the bolt  14  from moving into the casing  12 . To keep the projection steady within the hooked portion the slit may include a slight annular recess (not shown). 
     It is the slider  26  that provides the motion for the movement of the bolt  14  into and outward of the casing  12 . To enable the slider  26  to be movable by both the primary (key) and secondary (electric motor) locking mechanisms requires a clutch mechanism that is now described. 
     The secondary locking means includes a rack  44  that is adapted to engage the slider  26 . The rack  44  includes at one end splines  46  that are driven by a gear  48  rotatably driven by a shaft  102  extending from the electric motor  100 . The other end of the rack includes a generally oval-shaped cavity  50  which extends only partially therethrough. An outwardly biased pin  52  is positioned within the cavity  50  such that in its rest position, it extends beyond  53  of the rack  44 . The pin  52  contains a recess for housing the biasing member which in this case is a spring  54 . These parts of the lock can be seen more clearly in the exploded views of  FIGS. 3-4 . 
     The slider  26  further includes an arm  56  with an aperture  58  extending therethrough. The aperture  58  is generally of the same shape as cavity  50  in rack  44 . Housed within aperture  58  is a cap  60  including a tapered shoulder  62  terminating into a head  64 . It should therefore be apparent that when aperture  58  and cavity  50  are coaxially aligned, pin  52  will be pushed through aperture  58  and abut the lower surface of cap  60 . Arm  56  includes a recess  67  to allow for movement corresponding with the primary locking mechanism which will be later explained. 
     Further included is a carriage  68 . Carriage  68  includes a carriage pocket  70  and carriage aperture  72  extending therethrough. A lock barrel or cylinder  74  rotatably fixed to the casing  12  includes a cam  76  that upon rotation of the key barrel is correspondingly rotated. The cam  76  is adapted to be housed within carriage aperture  72  and during the locking and unlocking processes, the cam  76  correspondingly follows the movement of the carriage  68 . It is during this process that recess  67  is required to allow for the cam rotation. Carriage  68  is shiftable along slider  26  to the extent provided by a locking cavity  78  on arm position. As there is no force provided by cam  76 , the cap  60  remains in the central position of the pocket  70  thereby allowing pin  52  to constantly abut surface  88 . Then, on operation of the electric motor to unlock the bolt  14 , the pin  52  acts on surface  90  of slider aperture  58  to shift the slider  26  in the opposite direction. 
     One can thus appreciate that the above operation, in using a secondary locking mechanism, is capable of locking and unlocking the lock  10  independent of the primary locking mechanism, that being operative use of the cam  76 . 
       FIGS. 6-9  illustrate the primary locking mechanism which involves the use of a key being inserted into the key barrel and rotated, thereby rotating cam  76 . More specifically,  FIG. 6  illustrates the way the primary locking mechanism may function while the secondary locking mechanism is disengaged,  FIG. 7  illustrates a continuation of this same locking action, while  FIGS. 8 and 9  illustrate the fully locked and fully unlocked configurations of the lock  10  respectively. 
     Those skilled in the art would appreciate that when cam  76  is rotated in order to lock the lock  10 , it is caused to abut surface  92  of carriage aperture  72 . Therefore, carriage  68  is forced to longitudinally shift relative to the slider  26 . As can be seen in  FIG. 6 , this action causes tapered surface  82  of carriage pocket  70  to push against tapered shoulder  62  of cap  60 . Cap  60  is forced into its carriage frame and the tapered surfaces continue to slide until the side of head  64  of cap  60  abuts with surface  94  of pocket  70 . This action not only causes pin  52  to be forced into cavity  50  due to the force applied by cap  60 , but also provides for a mechanical connection between the cam  76  and the slider  26  to thereby shift the slider  26  with further rotation of the cam  76 . Essentially, connection between the slider  26  and rack  44  is broken due to the resulting shear plane between rack and slider while connection between slider  26  and cam  76  is achieved. 
     With continued rotation of the cam  76 , the bolt is drawn into the extended and deadlocked position. It is to be understood that the deadlocked configuration of the bolt  14  is not achieved through the primary locking mechanism but rather through pocket  40 . If the primary locking mechanism did involve its own deadlocking feature, unlocking the bolt  14  using the secondary locking mechanism would not be possible. It should therefore be clear that the present invention provides for two independent means of locking and unlocking bolt  14 . 
     When unlocking lock  10 , which is to drive bolt  14  within the casing  12 , the key is obviously rotated in the opposite direction. Therefore, cam  76  is forced to abut with surface  96  of carriage aperture  72  thereby causing carriage  68  to shift in the opposite direction as described above, with the cap  64  forced to abut the opposite surface of carriage pocket  70 . 
     In the situation where the bolt has been unlocked using the primary locking mechanism and is required to be locked once again using the secondary locking mechanism, the electric motor when operated will drive the rack until the rack cavity  50  is coaxially aligned once again with slider aperture  58  such that spring  54  forces pin  52  back into abutment with cap  60  such that the slider  26  and rack  44  are now re-coupled for the electric motor to drive the lock. 
     One can thus appreciate how the present invention may be used to unlock a lock that has been locked by an electric motor that is still in the locked position. This is advantageous where the electric lock is to be overridden or where it has broken down. Use of the primary locking mechanism thus allows the lock to still operate even where the electric motor can no longer function. 
     It is to be understood that once the secondary locking mechanism has been disengaged, it remains motionless due to the gearing of the electric motor. Essentially, gearing back movement is prevented and thereby allows sufficient force to be applied to the slider to overcome tension that may be acting on the slider due to pin  52  which remains outwardly biased. 
     In a further aspect of the invention, the actions of the electric motor may well be governed by the use of a microprocessor in electrical connection with both the electrical motor and an arrangement of micro-switches which sense whether the slider is in a locked or unlocked position. The primary function of the processor is to process information gained from the micro-switches and to correspondingly operate the electric motor. One advantage to such a system over existing systems is that there is no longer the requirement for operating the motor for a predetermined amount of time to ensure that locking or unlocking has taken place and considerable battery power consumed in the process. 
     If under any circumstances the lock should fail to lock, the processor will realize that the lock is neither in a locked or unlocked state and sound an audible alarm to inform the user that the lock has not been successfully locked. 
     Further, the apparatus may well include a remote access means such as an infrared receiver such that locking and unlocking of the lock may be achieved from a remote location using a transmitting means. Further still, the apparatus may include an interrogation means so that a user may determine whether the bolt is in a locked or an unlocked position some distance away. 
     In some circumstances, a further bolt system may be engaged simultaneously with the dual lock of the present invention whereby the apparatus is in mechanical connection with one or more further bolts used to lock or unlock the door whereby the slider  28  is in mechanical connection with the bolts. 
     So as to keep the door from freely swinging when in the unlocked position, the lock mechanism may include a spring-loaded latch (not shown) being outwardly biased by a biasing means (not shown). 
     It is to be understood that other secondary driving means may equally well be employed. The rack may be acted upon by use of a manually operated crank (not shown). 
     In general the term deadlocking is intended to mean that when the lock is deadbolted, that the slider is effectively prevented from any slidable motion. 
     The above description generally referred to the slider being movable by a key activating the primary locking mechanism and an electric servomotor driving the secondary locking mechanism. It may equally well be, however, that the secondary locking mechanism is also activated by the use of a solenoid. However the electric motor provides much higher torques required especially where the lock arrangement includes multiple bolts such as additional upper and lower bolts. Even further still the secondary locking mechanism may also include a key activated lock accessible from one or both sides of the lock case or other types of simple non-secure actuators. 
     The present invention may also equally well be adapted for use on existing doors by the use of simple but effective adaptive pieces. 
     Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus. 
     In any claims that follow and in the summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprising” is used in the sense of “including”, i.e. the features specified may be associated with further features in various embodiments of the invention.

Summary:
The present invention relates to a dual lock apparatus ( 10 ) of the type including a locking bolt ( 14 ) moveable between a first locked position and a second unlocked position said bolt movement corresponding with longitudinal movement of a slider ( 26 ) said apparatus including a first and a second locking means adapted to operate independently of one another. The first locking means ( 74 ) includes a rotatable cam ( 76 ) such that when rotated said cam acts against a moveable piston to thereby move said piston from a first position to a second position in which the second locking means becomes disengaged from said slider and further rotation of the cam urges longitudinal movement of the slider. The second locking means includes an electric motor in geared connection to a member ( 44 ) moveable between a first position and second position corresponding with the locked and unlocked positions of the bolt said member including an outwardly biased pin ( 52 ) adapted to engage the piston cylinder ( 58 ) and urge said piston into said piston first position to thereby mechanically connect the second locking means with the slider. The locking means can therefore operate independently of one another.