Abstract:
An anti-picking cylinder lock including a lock body, a plug defining a keyway, a plurality of telescopic body pin assemblies, each of the telescopic body pin assemblies including an outer body pin and an inner body pin and a plurality of telescopic plug pin assemblies, each of the telescopic plug pin assemblies including an outer plug pin and an inner plug pin, wherein at least one of the outer plug pins and the outer body pins is formed with at least one inner facing recess configured and arranged such that, upon an attempted picking of the lock, a portion of at least one of the inner plug pins and the inner body pins tends to engage the at least one recess, thus causing at least one of the inner plug pins and the inner body pins to move together in at least one direction.

Description:
REFERENCES TO RELATED APPLICATIONS 
   This application is the US national phase of international application PCT/IL2003/000523 filed 19 Jun. 2003 which designated the U.S. and claims benefit of Israel Patent Application No. 150,362 filed 20 Jun. 2002, the entire contents of both of which applications are incorporated by reference. 
   FIELD OF THE INVENTION 
   The present invention relates to locks generally and more particularly to cylinder locks having telescopic pins. 
   BACKGROUND OF THE INVENTION 
   The following US Patents are believed to represent the current state of the art: 
   U.S. Pat. Nos. 4,142,389; 5,123,268; 5,520,035 and 5,839,308. 
   SUMMARY OF THE INVENTION 
   The present invention seeks to provide an improved cylinder lock having telescopic pins. 
   There is thus provided in accordance with a preferred embodiment of the present invention, an anti-picking cylinder lock including a lock body defining a bore for rotatably accommodating a plug, the lock body having formed therein a plurality of body pin bores, a plug rotatably disposed in the bore, the plug defining a keyway which is adapted to receive a key, the plug having formed therein a plurality of plug pin bores arranged to correspond with the plurality of body pin bores, a plurality of telescopic body pin assemblies disposed at least partially in the plurality of body pin bores, each of the telescopic body pin assemblies including an outer body pin and an inner body pin disposed in a bore formed in the outer body pin and a plurality of telescopic plug pin assemblies disposed at least partially in the plurality of plug pin bores, each of the telescopic plug pin assemblies including an outer plug pin and an inner plug pin disposed in a bore formed in the outer plug pin, characterized in that at least one of the outer plug pins and the outer body pins is formed with at least one inner facing recess configured and arranged such that upon attempted picking of the lock, a portion of at least one of the inner plug pins and the inner body pins tends to engage the at least one recess, thus causing at least one of the inner plug pins and the inner body pins to move together in at least one direction. 
   Preferably, the at least one recess is formed on an outer plug pin. Alternatively, the at least one recess is formed on an outer body pin. 
   In accordance with another preferred embodiment, the at least one recess includes a plurality of mutually spaced recesses. Preferably, the at least one recess includes an annular recess defining at least one inner pin engagement shoulder. 
   In accordance with another preferred embodiment, the portion of at least one of the inner plug pins and the inner body pins includes a protrusion. Alternatively, the portion of at least one of the inner plug pins and the inner body pins includes an annular protrusion. Additionally, the protrusion defines at least one inner recess engagement shoulder. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
       FIGS. 1A and 1B  are sectional illustrations of a cylinder lock constructed and operative in accordance with a preferred embodiment of the present invention in respective locked and unlocked operative orientations; 
       FIGS. 2A and 2B  are illustrations of the lock of  FIGS. 1A and 1B  being picked,  FIG. 2A  being a sectional illustration and  FIG. 2B  being a partially end view illustration taken along arrow II in  FIG. 2A  and a partially sectional illustration taken along lines IIB—IIB in  FIG. 2A ; 
       FIGS. 3A ,  3 B and  3 C are sectional illustrations taken along lines III—III in  FIG. 1A  of a first type of telescopic pin arrangement constructed and operative in accordance with a preferred embodiment of the present invention in respective locked and first and second attempted picking orientations; 
       FIGS. 4A ,  4 B and  4 C are sectional illustrations taken along lines IV—IV in  FIG. 1A  of a second type of telescopic pin arrangement constructed and operative in accordance with a preferred embodiment of the present invention in respective locked and first and second attempted picking orientations; and 
       FIGS. 5A ,  5 B and  5 C are sectional illustrations taken along lines V—V in  FIG. 1A  of a third type of telescopic pin arrangement constructed and operative in accordance with a preferred embodiment of the present invention in respective locked and first and second attempted picking orientations. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Reference is now made to  FIGS. 1A and 1B , which are sectional illustrations of a cylinder lock constructed and operative in accordance with a preferred embodiment of the present invention in respective locked and unlocked operative orientations. 
   As seen in  FIGS. 1A and 1B , there is provided a cylinder lock comprising a lock body  10  defining a bore  12  in which is rotatably disposed a plug  14  defining a keyway  16  which is adapted to receive a key  17  ( FIG. 1B ). A plurality of body pin bores  18  are formed in lock body  10  and a corresponding plurality of plug pin bores  20 , each having a central axis  21 , are formed in plug  14 , communicating with keyway  16 . 
   Disposed in body pin bores  18  are telescopic body pin assemblies  22 , each of which preferably comprises an outer body pin  24 , which is spring loaded by a compression coil spring  26 , which is seated on a spring seat  28 . Disposed interiorly of outer body pin  24  and being linearly displaceable with respect thereto is an inner body pin  30 , which is spring loaded relative to outer body pin  24  by a compression coil spring  32 , which is seated on a neck portion  34  of the outer body pin  24 . 
   Disposed in plug pin bores  20  are telescopic plug pin assemblies  42 , each of which preferably comprises an outer plug pin  44  and, disposed interiorly of outer plug pin  44  and linearly displaceable with respect thereto, an inner plug pin  46 . Outer body pin  24  and outer plug pin  44  preferably define respective normally touching engagement surfaces  48  and  49 . 
   As seen in the enlargement of  FIG. 1A , the inner body pin  30  preferably comprises a shank portion  50  having a truncated conical head  52  at one end thereof. Formed at an opposite end of shank portion  50  is an enlarged cylindrical portion  54  having a radius which is only slightly less than that of an interior bore  56  in outer body pin  24 . 
   On the opposite side of enlarged cylindrical portion  54  from shank portion  50  is a truncated conical portion  58  which terminates in a narrowed cylindrical portion  60 . Adjacent to narrowed cylindrical portion  60  is a second enlarged cylindrical portion  62  typically having the same radius of enlarged cylindrical portion  54  but a thickness which is substantially smaller than enlarged cylindrical portion  54 . Inner body pin  30  terminates in a truncated conical portion  64  defining a plug pin engagement surface  66 . 
   The inner plug pin  46  preferably comprises a shank portion  70  having a truncated conical head  72  at one end thereof facing keyway  16 . Formed at an opposite end of shank portion  70  is an enlarged cylindrical portion  74  having a radius which is only slightly less than that of an interior bore  76  in outer plug pin  44 . On the opposite side of enlarged cylindrical portion  74  from shank portion  70  is a truncated conical portion  78 , defining a body pin engagement surface  80 . 
   In accordance with a preferred embodiment of the present invention, an annular recess  90  is formed in an inwardly facing wall of bore  76  adjacent to but not aligned with enlarged cylindrical portion  74 . As will be described in detail hereinbelow, this recess is operative to increase the difficulty of picking the telescopic plug pin assembly  42 . 
   In the illustration of  FIGS. 1A and 1B , a number of different plug configurations are shown, it being appreciated that similar or different plug configurations may or may not be employed in a given lock. 
   Reference is now made to  FIGS. 2A and 2B , which show the lock of  FIGS. 1A and 1B  being picked in a typical picking situation. 
   As seen in  FIG. 2B  a first picking tool  96  is employed to raise outer plug pin  44  while a second picking tool  98  engages the keyway  16  and applies a rotation torque thereto and thus to plug  14  as indicated by arrow  95 . It is seen in the enlargement of  FIG. 2B  that application of torque to plug  14  in the direction of arrow  95  during picking causes the inner body pin  30  to be skewed with respect to interior bore  56  and simultaneous raising of outer plug pin  44  causes second enlarged cylindrical portion  62  and truncated conical portion  64  to be aligned with recess  90 . As seen in  FIG. 2B , a shoulder  202  of second enlarged cylindrical portion  62  engages a corresponding shoulder  204  of recess  90 . This engagement may be useful in causing a person picking the lock to mistakenly assume that he has brought engagement surfaces  48  and  49  of respective outer body and plug pins  24  and  44  to the shear line  99  between the plug  14  and the body  10 . 
   Reference is now made to  FIGS. 3A ,  3 B and  3 C, which are sectional illustrations of a first type of telescopic pin arrangement constructed and operative in accordance with a preferred embodiment of the present invention in respective locked and first and second attempted picking orientations. As seen in  FIGS. 3A–3C , a telescopic pin assembly  300  is seen disposed partially in a bore  318  of lock body  310  and in a bore  320  of plug  314  and extends partially into keyway  16 . The central axis of bore  320  is designated by reference numeral  321 . 
   Telescopic pin assembly  300  preferably includes a telescopic body pin assembly  322 , which preferably comprises an outer body pin  324 , having a partially conical outer configuration. Outer body pin  324  is spring loaded by a compression coil spring  326 , which is seated on a spring seat  328 . Disposed interiorly of outer body pin  324  and being linearly displaceable with respect thereto is an inner body pin  330 , which is spring loaded relative to outer body pin  324  by a compression coil spring  332 , which is seated on a neck portion  334  of the outer body pin  324 . 
   Disposed in plug pin bore  320  is a telescopic plug pin assembly  342 , which preferably comprises an outer plug pin  344  and, disposed interiorly of outer plug pin  344  and linearly displaceable with respect thereto, an inner plug pin  346 . Outer body pin  324  and outer plug pin  344  preferably define respective normally touching engagement surfaces  348  and  349 . 
   The inner body pin  330  preferably comprises a shank portion  350  having a truncated conical head  352  at one end thereof which is sized so as to have a diameter larger than a corresponding shoulder  353  of outer body pin  324 . Formed at an opposite end of shank portion  350  is an enlarged cylindrical portion  354  having a radius which is only slightly less than that of an interior bore  356  in outer body pin  324 . 
   On the opposite side of enlarged cylindrical portion  354  from shank portion  350  is a truncated conical portion  358  which terminates in a narrowed cylindrical portion  360 . Adjacent to narrowed cylindrical portion  360  is a second enlarged cylindrical portion  362  typically having the same radius of enlarged cylindrical portion  354  but a thickness which is substantially smaller than enlarged cylindrical portion  354 . Inner body pin  330  terminates in a truncated conical portion  364  defining a plug pin engagement surface  366 . 
   The inner plug pin  346  preferably comprises a shank portion  370  having a truncated conical head  372  at one end thereof facing keyway  16 . Formed at an opposite end of shank portion  370  is an enlarged cylindrical portion  374  having a radius which is only slightly less than that of an interior bore  376  in outer plug pin  344 . On the opposite side of enlarged cylindrical portion  374  from shank portion  370  is a truncated conical portion  378 , defining a body pin engagement surface  380 . 
   In accordance with a preferred embodiment of the present invention, an annular recess  390  is formed in an inwardly facing wall of bore  376  adjacent to but not aligned with enlarged cylindrical portion  374 . As will be described in detail hereinbelow, this recess is operative to increase the difficulty of picking the telescopic plug pin assembly  342 . 
     FIG. 3B  shows a first typical picking situation when, as shown in  FIG. 2B , a first picking tool  96  is employed to raise the outer plug pin while a second picking tool  98  engages the keyway  16  and applies a rotation torque thereto and thus to the plug as indicated by arrow  395 . 
   It is seen in  FIG. 3B  that application of torque to plug  314  in the direction of arrow  395  during picking causes plug  314  to rotate slightly in a clockwise direction as indicated by arrow  395  and as indicated by the clockwise rotation of central axis  321  designated by A. This rotation produces engagement between a clockwise facing wall portion  315  of plug bore  320  with corresponding outer wall portions  316  and  317  of corresponding outer body pin  324  and outer plug pin  344 . This engagement pushes a base portion  319  of outer body pin  324  slightly in a clockwise direction causing a clockwise facing edge  323  thereof to engage a corresponding wall portion  325  of bore  318  and increasing the normal separation between an oppositely facing edge  327  of outer body pin  324  from a corresponding wall portion  329  of bore  318 , thus skewing outer body pin  324  relative to bore  318 . 
   Skewing of outer body pin  324  relative to bore  318  causes the inner body pin  330  to be skewed with respect to interior bore  356 . Simultaneous raising of outer plug pin  344  causes second enlarged cylindrical portion  362  and truncated conical portion  364  to be aligned with recess  390 . As seen in  FIG. 3B , a shoulder  392  of second enlarged cylindrical portion  362  engages a corresponding shoulder  394  of recess  390 . This engagement may be useful in causing a person picking the lock to mistakenly assume that he has brought engagement surfaces  348  and  349  of respective outer body and plug pins  324  and  344  to the shear line  399  between the plug  314  and the body  310 . 
   It is seen in  FIG. 3B  that truncated conical head  352  is positioned adjacent to and resting upon shoulder  353  of outer body pin  324 , 
     FIG. 3C  shows a second, further picking situation when the first picking tool  96  ( FIG. 2B ) is employed to raise the outer plug pin  344  further while the second picking tool  98  ( FIG. 2B ) continues to engage the keyway  16  and apply a rotation torque thereto and thus to the plug  314  as indicated by arrow  395 , producing rotation of the plug  314  as indicated by further clockwise rotation of central axis  321  designated by B. 
   It is seen in  FIG. 3C  that further raising of outer plug pin  344  causes outer body pin  324  and inner body pin  330  to be raised together due to the engagement of truncated conical head  352  of inner body pin  330  with shoulder  353  of outer body pin  324 . Thus, as seen in  FIG. 3C , when the junction between respective normally touching engagement surfaces  348  and  349  of outer body pin  324  and outer plug pin  344  is raised to lie at the shear line  399  between body  310  and plug  314 , inner body pin  330  spans the shear line  399 , preventing unlocking of the lock. 
   Furthermore, as seen in  FIG. 3C , continued application of torque to plug  314  in the direction of arrow  395  during picking causes plug  314  to rotate further in a clockwise direction as indicated by arrow  395 . The resulting engagement between clockwise facing wall portion  315  of plug bore  320  with corresponding outer wall portion  317  of outer plug pin  344  pushes outer plug pin  344  further in a clockwise direction causing full seating of enlarged cylindrical portion  362  of inner body pin  330  in recess  390 , engagement of outer plug pin  344  with cylindrical portion  360  of inner body pin  330  and resulting forcing of cylindrical portion  354  of inner body pin  330  clockwise against a facing wall of bore  356  defined by outer body pin  324 . The various inner and outer body and plug pins are thus seen to be spatially, axially and angularly offset from each other and locked together as well as being frictionally bound together by forced engagement therebetween, thus rendering picking increasingly difficult. 
   Reference is now made to  FIGS. 4A ,  4 B and  4 C, which are sectional illustrations of another type of telescopic pin arrangement constructed and operative in accordance with a preferred embodiment of the present invention in respective locked and attempted picking orientations. As seen in  FIGS. 4A–4C , a telescopic pin assembly  400  is seen disposed partially in a bore  418  of lock body  410  and in a bore  420  of plug  414  and extends partially into keyway  16 . The central axis of bore  420  is designated by reference numeral  421 . 
   Telescopic pin assembly  400  preferably includes a telescopic body pin assembly  422 , which preferably comprises an outer body pin  424 , having a partially conical outer configuration. Outer body pin  424  is spring loaded by a compression coil spring  426 , which is seated on a spring seat  428 . Disposed interiorly of outer body pin  424  and being linearly displaceable with respect thereto is an inner body pin  430 , which is spring loaded relative to outer body pin  424  by a compression coil spring  432 , which is seated on a neck portion  434  of the outer body pin  424 . 
   Disposed in plug pin bore  420  is a telescopic plug pin assembly  442 , which preferably comprises an outer plug pin  444  and, disposed interiorly of outer plug pin  444  and linearly displaceable with respect thereto, an inner plug pin  446 . Outer body pin  424  and outer plug pin  444  preferably define respective normally touching engagement surfaces  448  and  449 . 
   The inner body pin  430  preferably comprises a shank portion  450  having a truncated conical head  452  at one end thereof which is sized so as to have a diameter larger than a corresponding shoulder  453  of outer body pin  424 . Formed at an opposite end of shank portion  450  is an enlarged cylindrical portion  454  having a radius which is only slightly less than that of an interior bore  456  in outer body pin  424 . 
   On the opposite side of enlarged cylindrical portion  454  from shank portion  450  is a truncated conical portion  458  which terminates in a narrowed cylindrical portion  460 . Adjacent to narrowed cylindrical portion  460  is a second enlarged cylindrical portion  462  typically having the same radius of enlarged cylindrical portion  454  but a thickness which is substantially smaller than enlarged cylindrical portion  454 . Inner body pin  430  terminates in a truncated conical portion  464  defining a plug pin engagement surface  466 . 
   The inner plug pin  446  preferably comprises a shank portion  470  having a truncated conical head  472  at one end thereof facing keyway  16 . Formed at an opposite end of shank portion  470  is an enlarged cylindrical portion  474  having a radius which is only slightly less than that of an interior bore  476  in outer plug pin  444 . On the opposite side of enlarged cylindrical portion  474  from shank portion  470  is a truncated conical portion  478 , defining a body pin engagement surface  480 . 
   In accordance with a preferred embodiment of the present invention, a pair of mutually spaced annular recesses  490  is formed in an inwardly facing wall of bore  476  adjacent to but not aligned with enlarged cylindrical portion  474 . As will be described in detail hereinbelow, these recesses are operative to increase the difficulty of picking the telescopic plug pin assembly  442 . 
     FIG. 4B  shows a typical picking situation when, as shown in  FIG. 2B , a first picking tool  96  is employed to raise the outer plug pin while a second picking tool  98  engages the keyway  16  and applies a rotation torque thereto and thus to the plug as indicated by arrow  495 . 
   It is seen in  FIG. 4B  that application of torque to plug  414  in the direction of arrow  495  during picking causes plug  414  to rotate slightly in a clockwise direction as indicated by arrow  495  and as indicated by the clockwise rotation of central axis  421  designated by A. This rotation produces engagement between a clockwise facing wall portion  415  of plug bore  420  with corresponding outer wall portions  416  and  417  of corresponding outer body pin  424  and outer plug pin  444 . This engagement pushes a base portion  419  of outer body pin  424  slightly in a clockwise direction causing a clockwise facing edge  423  thereof to engage a corresponding wall portion  425  of bore  418  and increasing the normal separation between an oppositely facing edge  427  of outer body pin  424  from a corresponding wall portion  429  of bore  418 , thus skewing outer body pin  424  relative to bore  418 . 
   Skewing of outer body pin  424  relative to bore  418  causes the inner body pin  430  to be skewed with respect to interior bore  456 . Simultaneous raising of outer plug pin  444  causes second enlarged cylindrical portion  462  and truncated conical portion  464  to be aligned with one or the other of recesses  490  depending on the relative positions of the outer plug pin  444  and the inner body pin  430 . As seen in  FIG. 4B , a shoulder  492  of second enlarged cylindrical portion  462  engages a corresponding shoulder  494  of recess  490 . This engagement may be useful in causing a person picking the lock to mistakenly assume that he has brought engagement surfaces  448  and  449  of respective outer body and plug pins  424  and  444  to the shear line  499  between the plug  414  and the body  410 . 
   It is seen in  FIG. 4B  that truncated conical head  452  is positioned adjacent to and resting upon shoulder  453  of outer body pin  424 . 
     FIG. 4C  shows a second, further picking situation when the first picking tool  96  ( FIG. 2B ) is employed to raise the outer plug pin  444  further while the second picking tool  98  ( FIG. 2B ) continues to engage the keyway  16  and apply a rotation torque thereto and thus to the plug  414  as indicated by arrow  495 , producing rotation of the plug  414  as indicated by further clockwise rotation of central axis  421  designated by B. 
   It is seen in  FIG. 4C  that further raising of outer plug pin  444  causes outer body pin  424  and inner body pin  430  to be raised together due to the engagement of truncated conical head  452  of inner body pin  430  with shoulder  453  of outer body pin  424 . Thus, as seen in  FIG. 4C , when the junction between respective normally touching engagement surfaces  448  and  449  of outer body pin  424  and outer plug pin  444  is raised to lie at the shear line  499  between body  410  and plug  414 , inner body pin  430  spans the shear line  499 , preventing unlocking of the lock. 
   Furthermore, as seen in  FIG. 4C , continued application of torque to plug  414  in the direction of arrow  495  during picking causes plug  414  to rotate further in a clockwise direction as indicated by arrow  495 . The resulting engagement between clockwise facing wall portion  415  of plug bore  420  with corresponding outer wall portion  417  of outer plug pin  444  pushes outer plug pin  444  further in a clockwise direction causing full seating of enlarged cylindrical portion  462  of inner body pin  430  in recess  490 , engagement of outer plug pin  444  with cylindrical portion  460  of inner body pin  430  and resulting forcing of cylindrical portion  454  of inner body pin  430  clockwise against a facing wall of bore  456  defined by outer body pin  424 . The various inner and outer body and plug pins are thus seen to be spatially, axially and angularly offset from each other and locked together as well as being frictionally bound together by forced engagement therebetween, thus rendering picking increasingly difficult. 
   Reference is now made to  FIGS. 5A ,  5 B and  5 C, which are sectional illustrations of another type of telescopic pin arrangement constructed and operative in accordance with a preferred embodiment of the present invention in respective locked and attempted picking orientations. As seen in  FIGS. 5A–5C , a telescopic pin assembly  500  is seen disposed partially in a bore  518  of lock body  510  and in a bore  520  of plug  514  and extends partially into keyway  16 . The central axis of bore  520  is designated by reference numeral  521 . 
   Telescopic pin assembly  500  preferably includes a telescopic body pin assembly  522 , which preferably comprises an outer body pin  524 , having a partially conical outer configuration. Outer body pin  524  is spring loaded by a compression coil spring  526 , which is seated on a spring seat  528 . Disposed interiorly of outer body pin  524  and being linearly displaceable with respect thereto is an inner body pin  530 , which is spring loaded relative to outer body pin  524  by a compression coil spring  532 , which is seated on a neck portion  534  of the outer body pin  524 . 
   Disposed in plug pin bore  520  is a telescopic plug pin assembly  542 , which preferably comprises an outer plug pin  544  and, disposed interiorly of outer plug pin  544  and linearly displaceable with respect thereto, an inner plug pin  546 . Outer body pin  524  and outer plug pin  544  preferably define respective normally touching engagement surfaces  548  and  549 . 
   The inner body pin  530  preferably comprises a shank portion  550  having a truncated conical head  552  at one end thereof which is sized so as to have a diameter larger than a corresponding shoulder  553  of outer body pin  524 . Formed at an opposite end of shank portion  550  is an enlarged cylindrical portion  554  having a radius which is only slightly less than that of an interior bore  556  in outer body pin  524 . 
   On the opposite side of enlarged cylindrical portion  554  from shank portion  550  is a truncated conical portion  558  which terminates in a narrowed cylindrical portion  560 . Adjacent to narrowed cylindrical portion  560  is a second enlarged cylindrical portion  562  typically having the same radius of enlarged cylindrical portion  554  but a thickness which is substantially smaller than enlarged cylindrical portion  554 . Inner body pin  530  terminates in a truncated conical portion  564  defining a plug pin engagement surface  566 . 
   The inner plug pin  546  preferably comprises a shank portion  570  having a truncated conical head  572  at one end thereof facing keyway  16 . Formed at an opposite end of shank portion  570  is an enlarged cylindrical portion  574  having a radius which is only slightly less than that of an interior bore  576  in outer plug pin  544 . On the opposite side of enlarged cylindrical portion  574  from shank portion  570  is a truncated conical portion  578 , defining a body pin engagement surface  580 . 
   In accordance with a preferred embodiment of the present invention, an annular recess  590  is formed in an inwardly facing wall of bore  556  adjacent to but not aligned with enlarged cylindrical portion  574 . As will be described in detail hereinbelow, this recess is operative to increase the difficulty of picking the telescopic plug pin assembly  542 . 
     FIG. 5B  shows a typical picking situation when, as shown in  FIG. 2B , a first picking tool  96  is employed to raise the outer plug pin while a second picking tool  98  engages the keyway  16  and applies a rotation torque thereto and thus to the plug as indicated by arrow  595 . 
   It is seen in  FIG. 5B  that application of torque to plug  514  in the direction of arrow  595  during picking causes plug  514  to rotate slightly in a clockwise direction as indicated by arrow  595  and as indicated by the clockwise rotation of central axis  521  designated by A. This rotation produces engagement between a clockwise facing wall portion  515  of plug bore  520  with corresponding outer wall portions  516  and  517  of corresponding outer body pin  524  and outer plug pin  544 . This engagement pushes a base portion  519  of outer body pin  524  slightly in a clockwise direction causing a clockwise facing edge  523  thereof to engage a corresponding wall portion  525  of bore  518  and increasing the normal separation between an oppositely facing edge  527  of outer body pin  524  from a corresponding wall portion  529  of bore  518 , thus skewing outer body pin  524  relative to bore  518 . 
   Skewing of outer body pin  524  relative to bore  518  causes the inner body pin  530  to be skewed with respect to interior bore  556 . Simultaneous raising of inner plug pin  546  causes enlarged cylindrical portion  574  and truncated conical portion  578  to be aligned with recess  590 . As seen in  FIG. 5B , a shoulder  592  of enlarged cylindrical portion  574  engages a corresponding shoulder  594  of recess  590 . 
   It may be appreciated that lock picking can be done in various ways, is extremely dynamic and may result in any one of a variety of situations.  FIG. 5B  illustrates only one possible situation in which the picking of inner plug pin  546  results in a clockwise engagement of enlarged cylindrical portion  574  with a corresponding shoulder  594  of recess  590 , it being appreciated that other equally or more prevalent situations may occur during picking. This engagement may be useful in causing a person picking the lock to mistakenly assume that he has brought engagement surfaces  548  and  549  of respective outer body and plug pins  524  and  544  to the shear line  599  between the plug  514  and the body  510 . 
     FIG. 5C  shows a second, further picking situation when the first picking tool  96  ( FIG. 2B ) is employed to raise the outer plug pin  544  further while the second picking tool  98  ( FIG. 2B ) continues to engage the keyway  16  and apply a rotation torque thereto and thus to the plug  514  as indicated by arrow  595 , producing rotation of the plug  514  as indicated by further clockwise rotation of central axis  521  designated by B. 
   It is seen in  FIG. 5C  that due to the engagement of shoulder  592  of enlarged cylindrical portion  574  with a corresponding shoulder  594  of recess  590 , further raising of outer plug pin  544  causes outer body pin  524 , inner body pin  530  and inner plug pin  546  to be raised together therewith, thus preventing the junction of respective engagement surfaces  566  and  580  of inner body and plug pins  530  and  546  and the junction of respective engagement surfaces  548  and  549  of outer body and plug pins  524  and  544  from being located at the shear line  599  between the plug  514  and the body  510  at the same time. Thus, as seen in  FIG. 5C , when the junction between respective normally touching engagement surfaces  548  and  549  of outer body pin  524  and outer plug pin  544  is raised to lie at the shear line  599  between body  510  and plug  514 , inner plug pin  546  spans the shear line  599 , preventing unlocking of the lock. 
   Furthermore, as seen in  FIG. 5C , continued application of torque to plug  514  in the direction of arrow  595  during picking causes plug  514  to rotate further in a clockwise direction as indicated by arrow  595 . The resulting engagement between clockwise facing wall portion  515  of plug bore  520  with corresponding outer wall portion  517  of outer plug pin  544  pushes outer plug pin  544  further in a clockwise direction causing fall seating of enlarged cylindrical portion  574  of inner plug pin  546  in recess  590  and resulting forcing of base portion  519  of outer body pin  524  clockwise against a facing wall of bore  518  defined by body  510 . The various inner and outer body and plug pins are thus seen to be spatially, axially and angularly offset from each other and locked together as well as being frictionally bound together by forced engagement therebetween, thus rendering picking increasingly difficult. 
   It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications which would occur to persons skilled in the art upon reading the specification and which are not in the prior art.