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CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a Continuation-In-Part (CIP) of U.S. patent application S/N 11/423,959 filed on Jun. 14, 2006 by the Applicant, the disclosure of which is hereby incorporated herein in its entirety by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to cylinder-locks, and more particularly to cylinder locks with an external element mounted so as to be arranged for motion along the length of the cylinder lock body, which engages a helical cam of the cylinder lock, thus converting rotational motion of the key to linear motion. 
       BACKGROUND OF THE INVENTION 
       [0003]    The cylinder lock has been in use for more than 100 years as a standard apparatus for locking doors and other items such as containers. In common use nowadays is the European double cylinder lock apparatus  30 , also known as the ‘Haan’ profile lock, shown in prior art  FIG. 1 . 
         [0004]    The double cylinder lock apparatus  30  pictured in  FIG. 1 , comprises a key  32 , a double cylinder lock  34 , and a cam  36 . The standard components mounted on the cylinder lock  30  can be seen in  FIG. 2 , including a rotatable cylinder plug  35  ( FIG. 1 ) that is fastened in place by circlips  38 , and rotatable cam  36  having mounted inside it a coupling assembly  40 . Additional standard components such as pins and springs are not shown. 
         [0005]    The double cylinder lock apparatus  30  is operated as follows: the key  32  is rotated inside said cylinder lock  34  and the cam  36  is consequently rotated. In a mortise-type lock construction, for example, this rotation causes a displacement of a bolt (not shown) in the tangential direction to the motion of the cam  36 . The displacement of the bolt causes it, for example, to enter or exit a door jamb (not shown), that results in locking or unlocking of the door. In summary, the prior art uses a rotational motion which is converted to tangential motion in order to move said locking bolt(s). 
         [0006]    However, this is just one type of cylinder lock given as an example of the prior art. There are a multitude of variations of shapes and sizes of cylinder locks in existence. 
         [0007]    U.S. Pat. No. 2,637,196 to Seaver et al discloses a cylinder lock which is arranged to rotate a threaded spindle, on which a threaded sleeve is mounted. The sleeve is in front of the cylinder lock body and rotation of the lock causes the sleeve to move forward and backward. 
         [0008]    Another prior art example is shown in  FIG. 3 , in which a double cylinder lock fitted with a gear  44  is shown, as described in my previous work as a co-inventor, in U.S. Pat. No. 3,991,595, issued Nov. 16, 976. The difference between  FIG. 1 , and  FIG. 3 , is that instead of a cam  36  being utilized as in  FIG. 1 , a gear  44  is mounted to the cylinder lock  34 . The primary advantage of operating a cylinder lock  34  fitted with a gear  44  is the reduced rotational force needed to move larger or multiple locking bolts. Instead of using a single rotation of the key to provide the required force for moving the bolt(s), gear  44  can be arranged to drive a reduction gear, thus enabling the user to move the bolt(s) more easily, thus distributing the force needed to move the bolt(s) over a longer distance. 
         [0009]    Additionally it can be seen in  FIG. 4 , that the only component that has been changed from  FIG. 2 , is the gear  44 . The circlips  38  and the coupling assembly  40  remain the same in both prior art examples. 
         [0010]    In my previous work as a co-inventor, as described in U.S. Pat. No. 4,154,070 issued May 15, 1979, a lock was disclosed that causes insertion of multiple bolts into the jamb surrounding the door in multiple directions. The disadvantage of this design is that in order to install the device, a large section of the door interior volume needs to be removed, which is a difficult, time consuming and expensive process. In addition, the door structure itself is substantially weakened, reducing overall security. The lock is made of thin sheet metal and is not strong enough. 
         [0011]    Therefore, it would be desirable to provide an improved cylinder lock enabling design of more compact locks, with stronger materials, manufactured by advanced production technologies, at a reasonable price. The compact design will enable installation of the locks with minimal interference to the structural integrity of the door while at the same time utilizing components of the standard cylinder locks in use and in production around the world. 
       SUMMARY OF THE INVENTION 
       [0012]    Accordingly, it is a principal object of the present invention to overcome the disadvantages associated with the prior art and provide a cylinder lock having a body and a modified cam, the cylinder lock being adapted for moving an external element arranged to engage the modified cam, so that the external element slides axially on the cylinder lock body. 
         [0013]    The inventive cylinder lock enables compact design and low-cost production of various types of locks, with the entire cylinder lock being encased and fully protected from tampering or breakage by intrusion. The encased lock is designed for easy installation without weakening the door structure, and the lock utilizes as many standard components as possible to simplify and reduce the cost of the manufacturing process. 
         [0014]    In accordance with a preferred embodiment of the present invention, there is provided in a cylinder lock constructed as a body having a cylinder plug rotatably disposed therein, said cylinder plug having both a key end and an opposite end, the improvement comprising: 
         [0015]    a modified cam disposed at said cylinder plug opposite end, said cam having at least one thread, 
         [0016]    said cylinder lock being adapted for moving an external element arranged to engage said modified cam, 
         [0017]    said external element being arranged to slide along said cylinder lock body at least partially between said key end and said opposite end upon rotation of said cylinder plug. In a preferred embodiment, the inventive cylinder lock is designed to utilize a helical cam, and this design is hereinafter referred to as the HC cylinder lock. When the HC cylinder lock is operated by rotating the appropriate key within it, the external element is moved in a linear fashion along the length of the HC cylinder lock thus converting rotational motion to axial motion. This axial motion is used to position at least one locking bolt, of which the external element itself may be one, for the function of locking or unlocking a device. 
         [0018]    The external element has formed therein a threaded groove matching a helical threaded section formed on the helical cam, thereby enabling engagement of the external element and cam. 
         [0019]    The inventive HC cylinder lock construction enables more efficient usage of the hollow volume of a door for placement of a door lock incorporating the HC cylinder lock, since its streamlined design makes it possible to place it within this space. 
         [0020]    In an alternative embodiment, the modified cam comprises a protrusion extending radially from the cylinder plug of the cylinder lock, with the protrusion being adapted to engage a helical slot formed in the external element. The inventive cylinder lock can be utilized to provide several door locking mechanisms, including a security lock using a locking hasp and mounted on the external side of the door. The locking mechanism can be operated by the HC cylinder lock from either side of the door, with the locking mechanism encased and protected from all sides to prevent attempted intrusion. The locking bolts of the locking mechanism are operated by movement of the external element which slides in the axial direction along the HC cylinder lock body. The external element may be provided as a sleeve, or slider. 
         [0021]    The inventive HC cylinder lock can also be used with locking mechanisms utilizing multiple locking bolts. 
         [0022]    In another alternative embodiment, the inventive HC cylinder lock may be incorporated in a padlock replacement, using a multi-bolt locking mechanism fixedly mounted external to a door. The multi-bolt locking mechanism operates using an external element which slides along the length of the HC cylinder lock, to move the multiple locking bolts. The multiple locking bolts of the locking mechanism engage a locking hasp mounted to the doorpost. The entire HC cylinder lock and locking mechanism is encased and fully protected from tampering or breakage by unauthorized intrusion. 
         [0023]    In a further embodiment, the inventive HC cylinder lock can be incorporated in a high security, rotating bolt lock which engages a locking hasp, using a slider with an integrally formed actuator for developing bolt rotation by engaging an eccentric pin formed as part of the rotating bolt. The lock designed to be mounted on the external surface of a door at the entrance side. 
         [0024]    Additional features and advantages of the present invention will become apparent from the following drawings and description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    For a better understanding of the invention with regard to the embodiments thereof, reference is made to the accompanying drawings, not shown to scale, in which numerals designate corresponding elements or sections throughout, and in which: 
           [0026]      FIG. 1  is a prior art illustration showing a European profile double cylinder lock with a single tooth cam; 
           [0027]      FIG. 2  is an exploded view of some of the cylinder lock components shown in  FIG. 1 , featuring a cam, coupling and circlips; 
           [0028]      FIG. 3  is a prior art illustration showing a European profile double cylinder lock with a gear; 
           [0029]      FIG. 4  is an exploded view of several components of the cylinder lock shown in  FIG. 3 ; 
           [0030]      FIG. 5  is a perspective view of a preferred embodiment of a cylinder lock designed with a helical cam (HC) for enabling motion of an external element along the cylinder lock body, in accordance with the principles of the present invention; 
           [0031]      FIG. 6  is an exploded view of several components of the HC cylinder lock shown in  FIG. 5 , featuring a helical cam, coupling and circlips; 
           [0032]      FIG. 7  is a perspective view of the inventive HC cylinder lock, showing an external element arranged for sliding motion on the cylinder lock body; 
           [0033]      FIGS. 8-9  show, respectively, the position of the external element on front and rear ends of the HC cylinder lock body; 
           [0034]      FIG. 10  is a perspective view of another embodiment of the inventive HC cylinder lock, showing a reinforced-end external element arranged for sliding motion on a single cylinder lock body; 
           [0035]      FIGS. 11-12  show the external element in alternative positions on the HC single cylinder lock body; 
           [0036]      FIGS. 13-15  show an alternative external element design, featuring a single helical slot construction, arranged for sliding motion on a single cylinder lock body; 
           [0037]      FIG. 16  is an embodiment of a high security, multi-bolt lock equipped with the external element-type HC cylinder lock, which utilizes a single winged external element and an actuator having sloped surfaces, designed to be mounted on the external surface of a door at the entrance side; 
           [0038]      FIGS. 17-18  are perspective views of a section of a hollow steel door formed with mounting holes, showing a method for inserting a spacer used to support the door interior; 
           [0039]      FIG. 19  is a perspective view of the door section of  FIGS. 17-18 , after mounting the spacers; 
           [0040]      FIG. 20  is a front view of the door section having an auxiliary lock mounted on the external door section surface shown in  FIG. 19 ; 
           [0041]      FIG. 21  is a cross-sectional view of the door section shown in  FIG. 20 , taken along section lines A-A, showing the spacers used to support the door interior, with the external element-type HC cylinder lock mounted in position; 
           [0042]      FIGS. 22   a - b  show the operation of the actuator on the locking bolts of the high-security, multi-bolt lock equipped with the external element-type HC cylinder lock of  FIG. 16 ; 
           [0043]      FIG. 23  shows an alternative orientation of the high-security, multi-bolt lock equipped with the external element-type HC cylinder lock, featuring the operation of the actuator and locking bolts within a locking hasp; 
           [0044]      FIG. 24  is an exploded perspective view showing construction of a high security, rotating bolt lock equipped with the HC cylinder lock, which utilizes a slider as the external element with an integrally formed actuator for developing bolt rotation, with the lock designed to be mounted on the external surface of a door at the entrance side; 
           [0045]      FIG. 25  is a perspective view of the rotating bolt lock of  FIG. 42 , showing an enlargement of the HC cylinder lock, and the slider with integral actuator shaped to engage an eccentric pin formed as part of the rotating bolt, shown before engaging a locking hasp; 
           [0046]      FIG. 26  is a partial cutaway view of the locking hasp and the rotating bolt which engages it, illustrating the rotating bolt after engaging the locking hasp, before being rotated into the locked position; 
           [0047]      FIG. 27  is a perspective view of the rotating bolt lock of  FIGS. 42-44 , showing the rotating bolt rotated into the locked position; and 
           [0048]      FIGS. 28-31  show the rotating bolt lock, respectively, in a front view, a cross-sectional view taken along section lines C-C, a right-hand side view, and a cross-sectional view taken along section lines B-B. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0049]      FIGS. 1-4  representing the prior art have been described above in the Background. 
         [0050]    Referring now to  FIG. 5 , there is shown a preferred embodiment of a cylinder lock having a modified cam and being arranged for slidable, axial motion of an external element (not shown) along the cylinder lock body length, constructed and operated in accordance with the principles of the present invention. 
         [0051]    In the first example of a preferred embodiment of a double cylinder lock  34  arranged with an external element (see  FIGS. 7-9 ), the traditional cam  36  or gear  44  is replaced by a helical cam  48 . The cam is formed with at least one helical thread section, or more, as shown in following examples. The helical thread sections of the helical cam  48  can be designed for right or left-hand orientation with a variable pitch.  FIG. 6  shows an example of a helical cam  48  which has four helical thread sections and a right-hand orientation. In this design, a full rotation of the key causes the movable sleeve to slide approximately 30 mm, along the cylinder lock body which has a typical length of 76 mm. 
         [0052]    In  FIG. 5  it can be seen how the helical cam  48  is mounted in a standard double cylinder lock  34 , hereinafter referred to as a helical cam (HC) cylinder lock. It is important to note that the helical cam  48  is arranged to be mounted on the cylinder plug  35  in the same fashion with the circlips  38 , and replaces the standard cam  36  or gear  44  that are currently used with common cylinder locks. Similarly the interior cavity  50  of the helical cam  48  matches that of the standard cam  36  and gear  44  and therefore can accommodate the insertion of the coupling assembly  40 . The advantage of these design specifications is to ensure that only a minimum number of components need to be modified or replaced to incorporate the new technology into current lock manufacturing and production facilities. 
         [0053]    As shown in  FIG. 5 , an axial line A-A is drawn through the center of the circular part of the cylinder lock  34 , i.e. through the center of the section containing the keyway. Line A-A is also aligned with the center of the helical cam  48 . From hereinafter, usage of the term “axial direction” is to be understood as the direction coincident with the axial line A-A. 
         [0054]      FIG. 6  is an exploded view of several components of the HC cylinder lock  34  shown in  FIG. 5 , featuring a cam  48 , coupling  40  and circlips  38 . 
         [0055]      FIG. 7  is a perspective view of the inventive cylinder lock, showing the external element  52  provided as a movable sleeve arranged for sliding motion along the body of HC cylinder lock  34 . The external element  52  has an inner thread  54  which is designed to match the threaded sections formed on helical cam  48 . 
         [0056]    This embodiment of the device, comprising a key  32 , double cylinder lock  34 , helical cam  48 , external element  52  and all other cylinder lock internal components (not shown) shall hereinafter be called the external element-type HC cylinder lock  46 . 
         [0057]    In operation of the external element-type HC cylinder lock  46 , the rotation of key  32  inside cylinder lock  34  causes helical cam  48  to rotate, and the threaded sections of helical cam  48  engage the matching inner thread  54  of external element  52 . This engagement serves to translate the rotational motion of helical cam  48  into linear motion of external element  52  backwards or forwards in the axial direction, dependent on the direction of rotation of key  32 . The inner diameter of the sleeve-shaped external element  52  is designed to fit properly around the body of HC cylinder lock  34  to guide its motion in the axial direction with minimal friction. 
         [0058]      FIGS. 8-9  show, respectively, the position of the external element  52  on the key end and the opposite end of the HC cylinder lock  34  body. 
         [0059]    Referring now to  FIG. 8 , the external element  52  is positioned on the key end of the HC cylinder lock  34 . When key  32  is rotated 360 degrees, external element  52  becomes displaced the length of the HC cylinder lock  34  as it is driven by the rotation of helical cam  48 . The key  32  may then be removed after each full revolution. 
         [0060]    Referring now to  FIG. 9 , the new position of external element  52  is shown, for example, after a full revolution of key  32 . The example shown moves external element  52  from the key end of HC cylinder lock  34  to the opposite end along the axial direction of HC cylinder lock  34 . 
         [0061]    It can be seen that the profile  53  of HC cylinder lock  34  in  FIG. 8  is not the same as that of cylinder lock  56  in  FIG. 9 . This change was drawn to demonstrate that the concept being discussed can be applied to alternative profiles of cylinder locks. Additionally, there is no concern that there will be excessive displacement of external element  52 , causing it to disengage from the HC cylinder lock  34 , as movement of external element  52  will be guided by a housing (not shown) as well. 
         [0062]    In  FIGS. 10-12 , there is shown a single cylinder lock  60 . Mounted on single cylinder lock  60  is a variation of the external element shown with external element-type HC cylinder lock  46 . When compared with external element  52  which was shown earlier, it can be seen that this external element is shaped as a sleeve  62  with a reinforced end  64 , which is adapted to serve as a locking bolt. The reinforced-end external element  62  has the same helical thread  54  and diameter as external element  52 . 
         [0063]    This embodiment of the device, comprising a key  32 , a single cylinder lock  60 , rotatable cylinder plug  61 , helical cam  48 , reinforced-end external element  62  and common cylinder lock internal components (not shown) shall hereinafter be called the reinforced-end-type HC cylinder lock  58 . 
         [0064]    The advantage of reinforced-end type HC cylinder lock  58  is that it can be used itself as the locking bolt which will secure devices as will be explained below. 
         [0065]    Referring now to  FIG. 11 , reinforced-end-type HC cylinder lock  58  is shown in its retracted mode, i.e. reinforced-end external element  62  is in the closest position to the key  32 . 
         [0066]    In  FIG. 12  the key has been rotated a full turn and the reinforced-end external element  62  has moved in the axial direction, increasing the distance of the reinforced-end external element  62  from the key  32 , into the extended position. This extended mode can be used to lock devices as will be explained below. 
         [0067]    In the current example, the reinforced-end-type HC cylinder lock  58  may not require a full revolution of the key  32  to provide the movement desired. If the key  32  is turned about a quarter revolution, or about ninety degrees, this will result in a 7.5 mm movement by the reinforced-end external element  62 , which in the present embodiment will be sufficient to lock a device. 
         [0068]      FIGS. 13-15  show an alternative construction of an external element that operates on a similar rotation-to-axial motion principle as in the previous embodiment. 
         [0069]    This embodiment of the device, comprising a key  32 , a single cylinder lock  68 , pin  70 , roller  72 , helical slotted-reinforced-end external element  74  and internal components (not shown) shall hereinafter be called the helical slot, reinforced-end-type cylinder lock  66 . 
         [0070]    The reinforced-end external element  74  has a helical slot  76  that runs spirally along a portion of its length. The angle of the spiral slot facilitates axial motion of the external element as will be explained below. The helical slot, reinforced-end external element  74  is mounted on a single cylinder lock  68 , which has a pin  70  inserted in the cylinder plug  35  and arranged for rotation together with it. In the present embodiment, the pin has a roller  72  mounted on it. The roller  72  is inserted in the spiral slot  76  of the helical slot, reinforced-end external element  74  and serves to reduce friction during the motion of the pin  70  along the length of the helical slot  76 . The roller  72  is not an essential feature of the design. 
         [0071]    In operation, the helical slot, reinforced-end type cylinder lock  66  may be initially positioned in the locked or extended position shown in  FIG. 14 . When the key  32  is rotated about a quarter revolution inside the single cylinder lock  68 , it cannot be removed. The pin  70  rotates with the cylinder plug  61  by the same amount. It is important to note the pin  70  does not move in the axial direction with respect to the cylinder lock  68 . As the pin  70  rotates within helical slot  76  (as seen in  FIG. 16 ), the helical slot, reinforced-end external element  74  is moved in the axial direction. The retracted position of the helical slot, reinforced-end external element  74  with respect to the cylinder lock  68  is shown in  FIG. 15 . In this embodiment the ends of the slot  76  restrict the motion of the pin  70  and therefore the rotation of the key  32  to about a quarter revolution. 
         [0072]    In application, the extended position of the helical slot, reinforced-end type cylinder lock  66  can be used to lock a device, as the reinforced end  78  of the external element  74  can be utilized as a bolt. 
         [0073]      FIG. 16  is an exploded view of a modified multi-bolt, winged external element-type HC cylinder lock  80 , operated using HC cylinder lock  34 , especially designed as an auxiliary lock  82  to be mounted on the exterior face of a door  84  on the entrance side using an externally mounted locking hasp  86 . This embodiment features an external housing  88  integrally formed with an external escutcheon plate. Also shown mounted in the external housing  88  is a rotatable protection disc  89  that is designed to prevent drilling of the keyway. A single winged external element  90  has a partially circumferential sleeve portion  92 , unlike the external element  52  of  FIG. 7 . In this embodiment, single winged external element  90  is guided in its axial motion partially by the HC cylinder lock  34  body, and also by the external housing  88 , which supports one end of the HC cylinder lock  34 . 
         [0074]    The internal housing  94  supports the other end of HC cylinder lock  34 , and also provides guidance of the axial motion of single-winged external element  90 . The internal housing  94  and the external housing  88  are fastened together by a plurality of bolts  96 , forming a solid encasement  98  of the locking assembly containing HC cylinder lock  34 , thereby protecting it from any attempted tampering. Once the encasement  98  is completed, the entire construction can be mounted through the external surface of the door  84  by drilling a set of mounting holes  100 , with a main hole  102  with an approximate diameter of 40 mm for encasement  98 , and a set of auxiliary mounting holes  104  for securing internal escutcheon plate  106  with mounting screws  108 . 
         [0075]    Prior to installation of the encasement  98  containing the HC cylinder lock  34  within a hollow steel door, a pair of spacers  110  are placed within the hollow door via hole  102  and their ends are snap-fit within an additional set of auxiliary mounting holes  112 . Spacers  110  are provided to support the internal structure of the door  84 , so that when the internal escutcheon plate  106  is tightened against external housing  88  by tightening the mounting screws  108 , there is no risk of deformation of the door profile. The result of tightening the mounting screws  108  creates a strong mechanical connection between the door  84  structure and auxiliary lock  82 , greatly strengthening the mounting area of auxiliary lock  82  against forced entry and tampering. 
         [0076]    The locking hasp  86  is mounted to the external side of the door frame  114  by two strong mounting bolts  116 . Locking hasp  86  is engaged by a locking mechanism  118  (see  FIGS. 22   a - b ) comprising locking bolts  120  and  122 , which are seated in a locking compartment  124  which forms part of external housing  88 . Locking compartment  124  has both locking bolts  120 ,  122  seated therein in a normally open state, under spring force provided by spring  125 . Locking bolts  120 ,  122  are arranged to protrude from locking compartment  124  so as to engage locking bays  126  in locking hasp  86 . 
         [0077]    It is a particular feature of this embodiment that the external housing  88 , although shown in  FIG. 16  installed on the exterior face of door  84  on the entrance side, can be installed on the door within the dwelling or storage area, etc. In addition, depending on its mounting location, the encased locking assembly can be adapted as needed for use with sliding doors, single or double swinging doors, rolling shutters, etc. 
         [0078]    As shown, locking hasp  86  has patterned edges  127  which match those of the external housing  88 . When the door is in the closed position, these edges are capable of preventing an attempted intrusion or attack using a crowbar or other tool. 
         [0079]      FIGS. 17-18  are perspective views of a section of a hollow steel door formed with mounting hole  102 , showing a method for inserting a spacer used to support the door interior. The spacer may be inserted as part of the door production at the factory, or it may be inserted in mounting hole  102  formed in the door at the construction site. In either case, the spacer need not be welded to the door, thus simplifying the addition of the spacer to the door. 
         [0080]    In order to insert the spacer  110  through the hole  102 , a flat, standard screwdriver  128  is inserted into specially-designed slot  110   a  of spacer  110 , which has a slot width for gripping the screwdriver end, so that the spacer  110  does not fall within the door interior once inserted via hole  102 . The spacer  110  is shaped at each of both ends with a protrusion  110   b , and shoulders  110   c . When the spacer  110  is inserted through hole  102  using the screwdriver  128 , a first protrusion  110   b  is inserted into hole  112 , which serves as an anchor point. Then screwdriver  128  is rotated in the direction of arrow “G”, so that the spacer  110  forces the door surfaces  84   a - b  away from each other, enabling a second protrusion  110   b  to snap into place in hole  112 . The protrusions are designed to develop friction with the holes  112 , so as to maintain the spacer  110  in a desired orientation. The shoulders  110   c  are then aligned with the set of auxiliary mounting holes  104 . Tightening of mounting screws  108  creates a strong mechanical connection between the door  84  structure and auxiliary lock  82 . 
         [0081]      FIG. 19  is a perspective view of the door section of  FIGS. 17-18 , after mounting the spacers. 
         [0082]      FIG. 20  is a front view of the door section having the auxiliary lock  82  of  FIG. 1.6  mounted on the external door section surface shown in  FIG. 19 . 
         [0083]      FIG. 21  is a cross-sectional view of the door section shown in  FIG. 20 , taken along section lines A-A, showing the spacers  110  used to support the door interior, with the auxiliary lock  82  mounted in position. 
         [0084]    The operation of the auxiliary lock  82  embodiment of  FIG. 16  is now described. As shown in  FIG. 22   a , the wing portion of single winged external element  90  has formed at its distal end an actuator  134  having sloped surfaces. In a locking operation of HC cylinder lock  34 , actuator  134  engages sloped edges  136  of locking bolts  120 ,  122  as a result of axial motion of single-winged external element  90 . Thus, locking bolts are forced to slide apart and protrude from locking compartment  124 , so as to provide locking engagement with locking hasp  86 . 
         [0085]    As shown in  FIG. 22   b , reversal of the axial motion of the single-winged external element  90  by an unlocking motion of HC cylinder lock  34 , results in retraction of actuator  134 , and return of the locking bolts  120 ,  122  into the unlocked position when they slide together, by spring pressure (spring  125 —see  FIG. 16 ). 
         [0086]    In  FIG. 23 , a different orientation of the arrangement of locking hasp  86  is shown, featuring the locking mechanism  118  comprising locking bolts  120  and  122 . The operation of single winged external element  90  and actuator  134  is clearly visible against the sloped surfaces  136  of locking bolts  120 ,  122 . When the locking bolts  120 ,  122  are forced apart by actuator  134  in the direction of arrows F-F, each of them is urged into a locking cavity  135  formed at the opposite ends of locking bay  126 . Each of the locking cavities  135  is formed with a sloped surface  137  (see  FIG. 16 ). A feature of the design is the provision of sloped edges  138  on external ends of locking bolts  120 ,  122  to assist spring  125  in developing sliding motion of the locking bolts  120 ,  122  together under an opening force applied by the user to open the door  84 . The opening force will be transferred via the slopes  136  of locking cavity  135  to force locking bolts  120 ,  122  together, releasing them from locking cavity  135 . 
         [0087]      FIG. 24  is an exploded perspective view showing construction of a high security, rotating bolt lock  200  equipped with the double HC cylinder lock  34 . Rotating bolt lock  200  utilizes a slider  202  with an integrally formed actuator  204  for developing bolt rotation, with the lock designed to be mounted on the external surface of a door at the entrance side. The rotating bolt lock  200  can be mounted on the door during production of the door at the factory, or it can be mounted on a door at the construction site. Locking bolt  206  extends along an axis  208  which is perpendicular to the axis of rotation of the HC cylinder lock  34 , and bolt  206  extends along a bolt pin  210  which has the shape of an anchor at its locking end, and is formed with a truncated disc-shaped flat head  212  having a larger diameter than the bolt pin itself. An eccentric pin  214  formed on section  215  of bolt  206  at its actuation end engages a slot  216  formed in actuator  204 . 
         [0088]    Rotating bolt lock  200  is arranged to have one of its ends mounted in an internal housing  218  which is dimensioned so as to be mounted within a hole  102  formed in door  84 . The internal housing  218  and the external housing  220  are fastened together by screws  222  via mounting holes  223 , forming a solid encasement  224  of the locking assembly containing HC cylinder lock  34 , thereby protecting it from any attempted tampering. The mounting arrangement of lock  200  within door  84  is similar to that described in relation to the mounting arrangement of lock  82  as shown in  FIG. 16 . 
         [0089]    The locking hasp  230  is mounted to the external side of the door frame  114  by two strong mounting bolts  232  via mounting holes  233 . Locking hasp  230  is mounted so that its locking bay  234  becomes engaged with locking bolt  206  (see  FIGS. 25-31 ) during locking operation of the HC cylinder lock  34 . 
         [0090]    It is a particular feature of this embodiment that the external housing  220 , although shown in  FIG. 24  installed on the exterior face of door  84  on the entrance side, can be installed on the door within the dwelling or storage area, etc. In addition, depending on its mounting location, the encased locking assembly can be adapted as needed for use with sliding doors, single or double swinging doors, rolling shutters, etc. 
         [0091]      FIG. 25  is a perspective view of the rotating bolt lock  200  of  FIG. 24 , showing an enlargement of HC cylinder lock  34 , Slider  202  has a grooved section  231  which is designed to match the threaded sections formed on helical cam  48 . Slider  202  also has an integral actuator  204  shaped to engage eccentric pin  214  formed as part of the rotating locking bolt  206 , shown before engaging locking hasp  230 . Arrow  235  shows the direction of movement of the door  84  which brings rotating bolt  206  into engagement with locking hasp  230 . 
         [0092]    As shown in the perspective cutaway view of the locking hasp shown in  FIG. 26 , when the door  84  is closed, rotating bolt  206  engages locking hasp  230 , before bolt  206  is rotated into the locked position. From inside of the door  84 , operating knob  236  can be rotated to operate HC cylinder lock  34 . The operating knob  236  can also be operated by rotation of a key (not shown). 
         [0093]    As shown in the perspective view of  FIG. 26 , by rotation of the operating knob  236  as shown by arrow  238 , slider  202  moves forward and drives eccentric pin  214  so that rotating bolt  206  rotates into the locked position (arrow  240 ). 
         [0094]    As shown in  FIG. 27 , arrow H indicates a front view direction for a description of the rotating bolt  206  of lock  200 . Additional detail of the locking operation of rotating bolt  206  and the locked state of lock  200  can be seen in the drawing  FIGS. 28-31  which show, respectively, a front view ( FIG. 28 ), a cross-sectional view ( FIG. 29 ) taken along section lines C-C, a right-hand side view ( FIG. 30 ) and cross-sectional view ( FIG. 31 ) taken along section lines B-B. 
         [0095]    In the front view of  FIG. 28 , rotating bolt lock  200  is locked and the rotating bolt  206  engages locking hasp  230 , as shown in the cross-sectional view of  FIG. 29 . A locking flange  242  formed in locking hasp  230  engages the flat head  212  of rotating bolt  206 , thereby providing rotating bolt lock  200  with multi-directional locking. The rotating bolt  206  is secured within locking hasp  230  against motion in the vertical, horizontal and longitudinal directions, resulting in high security and preventing any attempt at tampering with the lock. 
         [0096]      FIGS. 30-31  show, respectively, the right-hand side view of rotating bolt  206  of lock  200 , and its corresponding cross-sectional view, providing further detail of the multi-directional locking feature of the rotating bolt lock  200  of the present invention. 
         [0097]    Having described the invention with regard to certain specific embodiments thereof, it is to be understood that the description is not meant as a limitation, since further modifications will now suggest themselves to those skilled in the art, and it is intended to cover such modifications as fall within the scope of the appended claims.

Summary:
A cylinder lock having a body and a modified cam, the cylinder lock being adapted for moving an external element arranged to engage the modified cam, so that the external element slides axially on the cylinder lock body. In a preferred embodiment, the inventive cylinder lock is designed to utilize a helical cam which engages a movable external element or slider, and this design is referred to as the HC cylinder lock. When operated by rotating the appropriate key within it, the movable external element can be moved in a linear fashion along the length of the HC cylinder lock thus converting rotational motion of the key to axial motion of the external element. The external element is arranged to engage an eccentric pin formed as part of a rotating bolt which rotates on an orthogonal axis to the cylinder plug in response to said sliding motion, for the function of locking or unlocking a device. The streamlined design of the inventive HC cylinder lock enables efficient placement of a door lock within the hollow volume of a door to provide locking action.