Abstract:
This invention relates to a lock cylinder, and in particular to a lock cylinder which can be fitted into a part of a lock assembly of a door or other openable panel. There is provided a lock cylinder ( 114; 214; 314; 414; 514; 614; 714 ) adapted for fitment into the lock housing ( 12 ), the lock cylinder comprising a key-operated locking part and an actuator ( 50 ), the lock cylinder having a predetermined profile for most of its length, and a securing part ( 70; 72,74; 76,78; 80,82; 170,172; 270,272; 370 ) projecting from the predetermined profile. The securing part is adapted to lie underneath a part of the lock assembly in use, such as a face plate of an operating handle of the lock assembly, so that the securing part prevents unauthorised removal of the lock cylinder through the face plate.

Description:
[0001]    This application claims priority of GB Patent Application 0700676.0, filed Jan. 13, 2007. 
       FIELD OF THE INVENTION 
       [0002]    This invention relates to a lock cylinder, and in particular to a lock cylinder which can be fitted into a lock housing of a door. 
       BACKGROUND OF THE INVENTION 
       [0003]    Many items of security hardware are available for fitment to a home or other building in order to make the building more secure. Many different manufacturers make such security hardware. It is not unusual for a manufacturer to make only some of the security hardware, and for example a particular manufacturer may make the key-operated lock cylinder which is supplied to other manufacturers who make the lock housings and other componentry to which the lock cylinder is fitted. 
         [0004]    In order to facilitate the use of componentry by others, it is known to make some of the componentry of a standard size and shape. One such standardised item are lock cylinders, which in Europe are substantially all made to the “Euro-profile”, i.e. a profile common to most if not all lock cylinders so that a lock housing manufacturer can make its lock housings to accommodate the standard profile in the knowledge that he can then purchase the standardised lock cylinder from one of several manufacturers. 
         [0005]    Typically, the lock cylinder will contain a key-operated locking part and an actuator, it being arranged that the actuator may be moved only upon insertion and rotation of the correct key into the locking part. The lock housing will contain componentry which can be moved by the actuator to effect unlocking and/or unlatching of the door. 
         [0006]    Many doors to which a lock housing is fitted require key-controlled access from both sides of the door, in which case the lock cylinder has two opposed locking parts with the actuator therebetween. The two parts are physically connected by a bridge, and each of the two opposed locking parts can be actuated by insertion and rotation of the correct key. In this way, insertion and rotation of the correct key into the lock cylinder from either side of the door causes rotation of the actuator and unlocking and/or unlatching of the door. 
         [0007]    Whilst the use of a standard lock profile has significant advantages for the security hardware industry, it also has a significant disadvantage. This is that an intending intruder can acquaint him or herself with the method of fitment of the lock to the housing, in the knowledge that almost any lock he or she will seek to overcome will have the same method of fitment. Accordingly, the intending intruder does not need to acquaint him or herself with many different methods of fitment, and therefore many different methods of gaining unauthorised access. 
         [0008]    This disadvantage has become increasingly well-known in relation to Euro-profile lock cylinders, and in order to better explain this disadvantage, reference is made to  FIG. 1  and  FIGS. 2   a - e  of the accompanying drawings, which show a prior art lock cylinder and its typical fitment into a door. 
         [0009]    As shown in  FIGS. 1 and 2   a - e , the typical locking componentry for a door  10  (only a small part of which is shown) comprises a lock housing  12 , a lock cylinder  14 , an inner face plate  16  carrying an inner handle  18 , and an outer face plate  20  carrying an outer handle  22 . (References to “inner” and “outer” herein relate respectively to the inside and outside of the door  10  in the normal orientation of use). 
         [0010]    The door  10  in this drawing is of extruded plastics, comprising a hollow door profile  24  of particular dimensions (the door profile  24  having certain standard dimensions and other non-standard dimensions which are peculiar to the particular manufacturer). 
         [0011]    The lock edge  26  of the door profile  24  is recessed or rebated (not shown) in order to accommodate the lock housing  12 , the lock housing  12  comprising a locking bolt  30  and a latch  32 , both of which in use can project from the locking edge  26  and into a keeper (not shown) fitted into the surrounding door frame (also not shown). 
         [0012]    Additional holes are made in the door profile  24  to accommodate other parts of the locking componentry, specifically the hole  34  is made to accommodate the lock cylinder  14 , the holes  36  to accommodate the drive bar  40  which interconnects the handles  18  and  22  (the lock housing  12  in this embodiment having two alternative locations  42  for the drive bar  40 ), and the holes  44  to accommodate the bolts  46  which interconnect the face plates  16  and  20 . It will be understood that the holes  34 ,  36  and  44  pass right through the door profile  24 . 
         [0013]    In typical fashion, the drive bar  40  actuates the latch  32  and the locking bolt  30 . The lock housing  12  will contain componentry to allow rotary movement (typically downwards rotary movement) of the handles  18 ,  22  to draw the latch  32  and bolt into the lock housing (and out of engagement with their respective keepers), and another rotary movement (typically an upwards rotary movement) to drive the locking bolt  30  into its keeper. The lock cylinder  14  is typically connected to componentry which can prevent rotation of the drive bar  40 . 
         [0014]    The lock housing has an opening  52  therethrough which is of substantially identical shape to the profile of the lock cylinder  14 , and is sized to accommodate the lock cylinder  14 , so that when the lock housing  12  is fitted into the door profile  24  the lock cylinder may be slid through the hole  34  and into the opening  52  of the lock housing. 
         [0015]    As is shown in  FIG. 2   c , the lock cylinder  14  is designed for key operation from both sides of the door, and therefore contains an inner part  54  and an outer part  56 . Each of the parts  54  and  56  contains a number of (in this embodiment six) cooperating pins and tumblers, arranged so that only upon insertion of the correct key  60  can the key be rotated and drive the actuator  50  to rotate. 
         [0016]    The two parts  54  and  56  of the lock cylinder  14  are interconnected by a bridge  62  which has a threaded aperture  64  formed therethrough. The threaded aperture  64  is adapted to receive a bolt  68  which is inserted through the hole  66  and by which the lock cylinder  14  can be secured to the lock housing  12 . 
         [0017]    Clearly, it is a useful safety feature that the bolt  68  can only be removed from the locking edge  26  of the door, to which access can only be gained whilst the door is open. Accordingly, when the door is closed and locked the intending intruder cannot remove the lock cylinder  14  by simply reversing the steps of fitment. 
         [0018]    Instead, however, it has become recognised that the bridge  62  is the weakest part of the lock cylinder  14 , and an intending intruder can seek to disable the lock by breaking the lock cylinder  14  at the bridge  62 . 
         [0019]    Specifically, the thickness of the bridge  62  is limited by the dimensions of the Euro-profile cylinder  14 , and it is not possible to increase the thickness and therefore the strength of the bridge. Also, the necessity to provide a threaded hole  64  in the bridge  62  with which the bolt can engage further weakens this area of the lock cylinder  14 . 
         [0020]    Accordingly, an intending intruder can seek to gain access to a locked building by applying a sideways force onto the outer end of the lock cylinder  14 , the sideways force being sufficient to break the bridge  62  adjacent to the bolt  68 . Once the bridge has been broken the two parts  54 , 56  of the lock cylinder  14  are no longer secured by the bolt  68 , and each part can be slid out of the lock housing  12 . Once the outer part  56  of the lock cylinder  14  has been removed, the intruder can insert a tool into the hole  34 ,  52  and manipulate the componentry of the lock housing  12  in order to unlock and/or unlatch the door  10 . 
         [0021]    Manufacturers have sought to prevent such a method of attack upon a locked door by reducing the sideways movement available to the lock cylinder  14 , and so reducing the sideways force which can be applied to the bridge. This is achieved by adding packing around the lock cylinder  14  and removing some or all of the free space which lies between the lock cylinder  14  and the hole  34  in the door. 
         [0022]    However, the above-stated method of attack upon the bridge is not the only method of attack, and it is also known to provide a tensile force upon the outer end  56  of the lock cylinder  14 , which force is transmitted directly (by way of the material of the lock cylinder itself to the bridge  62 . Specialist tools such as slide hammers and the like can impart sufficient tensile forces to break the bridge and pull out the outer part  56  of the lock cylinder  14 . Clearly, since no attempt is made to move the lock cylinder sideways, the above-stated defence is of no real benefit against this second method of attack. 
       SUMMARY OF THE INVENTION 
       [0023]    The inventor has therefore realised that another method and apparatus is required to seek to defend against the second method of attack. 
         [0024]    According to the present invention, therefore, there is provided a lock cylinder having a predetermined profile for most of its length, but including a projection to that profile at a chosen position. 
         [0025]    The predetermined profile will typically be the Euro-profile, and the use of such a profile for most of the length of the cylinder allows the invented lock cylinder to fit to standardised lock housings and other lock componentry. However, the provision of a projection to the profile at a chosen position enables the lock profile to be retained by a part of the lock componentry in the event that the bridge is broken. Accordingly, unlike the prior defences which all sought to prevent the bridge being broken, the present invention seeks to prevent the subsequent removal of parts of the lock cylinder even if the bridge is broken. If the intending intruder cannot remove parts of the lock cylinder after breaking the bridge then the likelihood of access being gained to the lock housing to unlock and/or unlatch the door is much reduced or prevented. 
         [0026]    Preferably, the projection is at least one securing pin. Preferably also the securing pin passes through a part of the lock cylinder adjacent to the locking componentry of the cylinder. 
         [0027]    The chosen position is such that the projecting securing pin(s) will lie underneath the face plate at the outer side of the door in use, so that it is necessary for the intending intruder to force the securing pin(s) through the face plate to remove a part of the locking cylinder. 
         [0028]    Removal of the part of the locking cylinder can be made more difficult by the provision of an additional security element and/or an additional security plate, both of which are adapted to lie underneath the face plate and increase the resistance to the securing pin(s) being forced therethrough. 
         [0029]    The securing pins can pass through a part of the lock cylinder made available by the absence of a part of the locking componentry, or by the re-positioning of the locking componentry. Alternatively, the securing pin(s) can project beyond the profile without encumbrance to the locking componentry of the lock cylinder. 
     
    
     
       BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS 
         [0030]    The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which: 
           [0031]      FIG. 1  shows an exploded view of a prior art arrangement comprising a lock housing and lock cylinder for a door; 
           [0032]      FIGS. 2   a - e  show various views of a prior art lock cylinder; 
           [0033]      FIGS. 3   a - d  show various views of a first embodiment of lock cylinder according to the invention; 
           [0034]      FIG. 4  shows the sectional view through a door fitted with a lock cylinder of  FIGS. 3   a - d;    
           [0035]      FIGS. 5   a - d  show various views of a second embodiment of lock cylinder according to the invention; 
           [0036]      FIG. 6  shows the sectional view through a door fitted with a lock cylinder of  FIGS. 5   a - d;    
           [0037]      FIGS. 7   a - d  show various views of a third embodiment of lock cylinder according to the invention; 
           [0038]      FIG. 8  shows the sectional view through a door fitted with a lock cylinder of  FIGS. 7   a - d;    
           [0039]      FIGS. 9   a - e  show various views of a fourth embodiment of lock cylinder according to the invention; 
           [0040]      FIG. 10  shows the sectional view through a door fitted with a lock cylinder of  FIGS. 9   a - e;    
           [0041]      FIGS. 11   a - c  show various views of an additional security element; 
           [0042]      FIG. 12  shows a view similar to that of  FIG. 6 , with the additional security element; 
           [0043]      FIGS. 13   a - c  show various views of the additional security plate; 
           [0044]      FIG. 14  shows a view similar to that of  FIG. 6 , with an additional security plate; 
           [0045]      FIG. 15  shows a pair of additional security plugs and their connecting bolt; 
           [0046]      FIG. 16  shows a view similar to that of  FIG. 6 , with the additional security plugs; 
           [0047]      FIGS. 17   a - d  show various views of a firth embodiment of lock cylinder according to the invention; 
           [0048]      FIG. 18  shows the sectional view through a door fitted with a lock cylinder of  FIGS. 17   a - d;    
           [0049]      FIGS. 19   a - e  show various views of a sixth embodiment of lock cylinder according to the invention; 
           [0050]      FIG. 20  shows the sectional view through a door fitted with a lock cylinder of  FIGS. 19   a - e;    
           [0051]      FIGS. 21   a - e  show various views of a seventh embodiment of lock cylinder according to the invention; and 
           [0052]      FIG. 22  shows the sectional view through a door fitted with a lock cylinder of  FIGS. 21   a - e;    
       
    
    
     DETAILED DESCRIPTION 
       [0053]    A detailed explanation of the prior art components and arrangements of  FIGS. 1-2   e  is provided above, and so will not be repeated. The present invention relates to a replacement for the lock cylinder  14 , and all of the other componentry can be retained (and is therefore given the same reference numerals in the following description). It will be understood that the form of the door profile  24  is not relevant to the present invention, and it will also be understood that the invention can be used with doors of other materials than plastics, and indeed for other applications than doors, where a standard profile lock cylinder such as a Euro-profile lock cylinder is used. 
         [0054]    The first embodiment of the present invention is shown in  FIGS. 3   a - 3   d  and  4 . It will be seen that one of the six sets of cooperating pins and tumblers which make up the locking componentry of the lock cylinder has been removed, and replaced by a securing pin  70  which passes through the body of the lock cylinder  114  and projects from the profile thereof. As seen in  FIG. 4 , the location of the securing pin  70  is chosen to lie beneath the outer face plate  20 . As shown in  FIG. 1  the face plates  16  and  20  have an opening  72  therethrough of substantially identical shape to the Euro-profile of the cylinder, and which openings can accommodate the lock cylinder  14 ,  114 . However, the securing pin  70  cannot pass through the opening  72  in the face plate  20  and the presence of the securing pin  70  therefore prevents removal of the outer part  56  of the lock cylinder  14  even if the bridge  62  is broken. 
         [0055]    It will also be understood from  FIG.1  that the face plate  20  is secured by way of bolts  46  (typically M5 or M6 bolts) which pass through the door profile  24  and secure the face plates  16  and  20  together. Specifically, the bolts  46  locate into blind threaded bores (not shown) in the rear surface of the face plate  20 . Without access to the inner end of the bolts  46  located on the inside of the door, the face plate  20  cannot be removed without destroying either the face plate or a part of the door, and it is extremely unlikely that the intending intruder will be prepared to, or able to, destroy either item, or will be armed with the tools necessary for that. 
         [0056]    In the second embodiment of  FIGS. 5   a - d  and  6 , the lock cylinder  214  has two securing pins  72 ,  74 , but is otherwise identical to the first embodiment described above. The provision of two securing pins increases the resistance to attempts to force the outer part  56  of the lock cylinder  214  through the face plate  20 . 
         [0057]    It will be understood that in the first and second embodiments described above, the locking componentry of the lock cylinder  114 ,  214  is modified, i.e. the number of cooperating pins and tumblers within the lock cylinder is reduced in order to accommodate the securing pin within a lock cylinder of identical dimensions. The use of five cooperating pins and tumblers does, however, reduce slightly the level of security of the lock cylinder, and it may be preferred to retain six cooperating pins and tumblers. 
         [0058]    In the embodiment of  FIGS. 7   a - d  and  8 , therefore, a lock cylinder  314  is provided, having identical outer dimensions to that of the second embodiments, but employing six cooperating pins and tumblers. The cooperating pins and tumblers are made of reduced size in order to fit within the available volume of the lock cylinder  314 , and yet accommodate the securing pins  76  and  78 . 
         [0059]    The fourth embodiment of  FIGS. 9   a - e  and  10  uses two separate but coaxial securing pins  80  and  82 . Since the pins  80 ,  82  do not pass through the body of the lock cylinder they do not foul the locking componentry, and the pins and tumblers of the lock cylinder  414  are substantially identical to those of the prior art lock cylinder  14 . Whilst this fourth embodiment provides the projection required to foul the face plate  20  upon intended removal of the outer part  56  of a broken lock cylinder, it is less preferred than the earlier embodiments as a securing pin which passes through the body of the lock cylinder will typically be able to withstand greater shear loads. 
         [0060]    It will be understood that in the embodiments of  FIGS. 4 ,  6 ,  8  and  10  it is the face plate  20  which prevents removal of the outer part  56  of the broken lock cylinder by virtue of the securing pin(s) fouling the face plate  20 . It is, however, known that some manufacturers provide relative thin and weak face plates, and in particular face plates through which an intending intruder may be able to force the securing pins.  FIGS. 11-14  show additional security components designed to reduce the likelihood of that. 
         [0061]      FIGS. 11   a - c  show an additional security element  84  which is made of pressed steel and has a plate part  86  with a hole  88  of Euro-profile therethrough to accept the lock cylinder  214  (in this embodiment, although the clip could equally be used with the other embodiments of lock cylinder, as desired). As shown in  FIG. 12 , in use the additional security element  84  is installed prior to fitment of the face plate  20  (the element  84  can be installed after the lock cylinder  214 , or alternatively can be installed before the lock cylinder  214  requiring the lock cylinder to be fitted from the inside of the door). The element  86  has a pair of resilient arms  90  which clip underneath an internal part of the door profile  24 . The lock cylinder securing pins  72 ,  74  fit underneath the plate part  86 , and if the bridge  62  is broken the intending intruder has to force the securing pins  72 ,  74  through the plate part  86  as well as through the face plate  20 . 
         [0062]    The additional security plate  92  of  FIGS. 13   a - c  is also of pressed steel, and is for a similar purpose to the additional security element  84 , but is of simpler design. The additional security plate  92  merely sits within the face plate  20  (see  FIG. 14 ) and acts to spread the load of any attempt to force the pins  72 ,  74  through the face plate  20  across a larger area of the face plate, so reducing the likelihood that such attempts will be successful. 
         [0063]      FIGS. 15 and 16  show a pair of additional security plugs  94 , one of which is fitted to the outside of the door, the other of which is fitted to the inside of the door. As seen in  FIG. 16 , the additional security plugs  94  are adapted to fit underneath the respective face plates  16 , 20 , and are secured together by a bolt  96 . The bolt  96  passes underneath the bottom edge (as viewed) of the lock housing  12 , or alternatively the lock housing  12  may contain a notch in its bottom edge or a hole for the bolt  96 . 
         [0064]    The additional security plugs  94  have formations  98  which are sized to fit within the hole  34 , and substantially fill the hole  34  so as to reduce or eliminate sideways movement of the lock cylinder within the hole  34 . The formations  98  surround an opening  100  through which the lock cylinder can be fitted. In this embodiment the additional security plugs  94  also have aligned holes  102  which accommodate the lower of the bolts  46  which interconnect the face plates  16  and  20 . 
         [0065]    In the embodiment of  FIG. 16  the additional security plugs  94  are used with a lock cylinder  114  of  FIGS. 3 and 4 , though it will be understood that they could alternatively be used with any of the lock cylinders previously described. 
         [0066]    The formations  98  are not continuous, but instead include a gap  104  which can accommodate the securing pin  70  (though it will be understood that in other embodiments two gaps, or one enlarged gap, could be provided to accommodate two securing pins such as  72  and  74 ; or  78  and  80 , if desired). 
         [0067]    It will be seen from  FIG. 16  that the securing pin  70  is located beneath the body of the external additional security plug  94 , and attempts to forcibly remove the lock cylinder  114  from the door will require the intending intruder first to break the lock cylinder  114  as previously described (which breakage is itself made more difficult because the additional security plug  94  substantially fills the hole  34 ), and then either to force the securing pin  70  through the body of the additional security plug  94  and then through the face plate  20 , or else to forcibly remove the additional security plug and the face plate from the door. It can be arranged that the additional security plug  94  is sufficiently robust to withstand even determined attempts to force the security pin  70  therethrough, and the bolt  96  which connects the two additional security plugs  94  will help to prevent the forced removal of the security plug. 
         [0068]    In the embodiment of  FIGS. 17   a - d  the security plug  194  is secured to the lock cylinder  514  as part of the assembly procedure, so that the lock cylinder  514  and security plug  194  are supplied as a single component for fitment to the profile  24 , which will make fitment easier for the installer. 
         [0069]    The securing pins  170 ,  172  are fitted through two slots  101  in the skirt of the security plug  194 . This allows the security plug  194  to move relative to the lock cylinder by a distance corresponding to the length of the slots  101 . In this embodiment the length of the slots  101  is 5 mm, and this length is chosen because lock cylinders are made in discrete lengths which differ in steps of 5 mm. Permitting 5 mm of movement between the security plug  194  and the lock cylinder  514  will ensure that the security plug can be correctly located within the hole  34  in the profile  24 , regardless of the thickness of the profile  24  and therefore regardless of the length of lock cylinder chosen to fit that profile. 
         [0070]    It will be seen from  FIG. 18  that in this embodiment the securing pins  170 ,  172  lie within the volume of the profile  24 , i.e. the pins  170 ,  172  are hidden below the surface of the profile (this feature can be shared by the other embodiment if desired). 
         [0071]    In the embodiment of  FIGS. 19 and 20 , the lock cylinder  614  is modified less than are the lock cylinders of the other embodiments. Specifically, in this embodiment the securing pins  270 ,  272  are fitted between the pins and tumblers and the actuator  50 . This avoids any requirement to reduce the number of pins and tumblers, or to modify a pin and tumbler. In addition, the installer can use an existing packer  103  to fill some or all of the free space between the lock cylinder  614  and the hole  34  in the profile  24 . As such, this embodiment is particularly suitable for retro-fitment to a panel which already incorporates a packer  103 . 
         [0072]    The embodiment of  FIGS. 21 and 22  uses a single securing pin  370 , and the lock cylinder  714  is modified over a standard lock cylinder by having a longer retaining plug in one of the pin and tumbler chambers. The retaining plug is fitted into the bottom of the pin and tumbler chamber to retain a spring in engagement with the pin and tumbler. The use of a longer retaining plug results in a reduced-length chamber, and the pin  370  passes through the elongated retaining plug. 
         [0073]    The use of the present invention does not preclude the use of other methods to seek to prevent breakage of the bridge, for example other methods of the packing of the free space between the lock cylinder and the hole  34 , for example. 
         [0074]    Clearly, the securing pins  70 ,  72 ,  74 ,  76 ,  78 ,  80 ,  82 ,  170 ,  172 ,  270 ,  272  and  370  are made sufficiently rigid to withstand the considerable shearing forces which may be applied by an intending intruder armed with a slide hammer or the like. The securing pins are preferably solid, and of hardened steel or the like. The securing pin(s) may for example be hardened steel roll or spiral pins, for example. In all of the embodiments shown the securing pin(s) project from both sides of the lock cylinder, and whilst that is preferred the use of one or more securing pins projecting from only one side of the lock cylinder is not thereby excluded.