Patent Publication Number: US-9890562-B2

Title: Locking arrangement

Description:
PRIORITY OF INVENTION 
     This application claims priority to South African Patent Application Number 2012/02067 that was filed on Mar. 20, 2012. The entire content of this application is hereby incorporated herein by reference. 
     FIELD OF INVENTION 
     This invention relates generally to a locking arrangement and an access control system. 
     BACKGROUND OF INVENTION 
     The Inventor is aware that current access control systems often make use of electro-magnetic locking arrangements for granting access to access-restricted areas (e.g. to control access to expensive equipment which needs to be protected against unauthorised access, e.g. by potential thieves). The disadvantage however of electro-magnetic locks are that they have to be powered all the time; draw large currents (i.e. up to 3 amps); are expensive; relatively difficult to install; and relatively heavy. 
     It is an object of this invention to provide means which the Inventor believes will at least alleviate some of the above identified problems. 
     SUMMARY OF INVENTION 
     In accordance with one aspect of the invention there is provided a locking arrangement which includes: 
     a body; 
     a locking member which is displaceable relative to the body, the locking member defining at least one striker element engagement formation which is configured to engage a striker element for part of its displacement relative to the locking arrangement along a predetermined displacement path, the locking member being displaceable between first and second spaced apart positions in each of which the engagement formation is positioned such that a said striker element is releasably engageable therewith and between which a said striker element is in engagement with the engagement formation; and 
     a securing mechanism configured to secure the locking member releasably in at least one of the first and second spaced apart positions. 
     The locking member may be angularly displaceable relative to the body, and the at least one striker element engagement formation of the locking member may be configured to engage a striker element for part of its displacement along the predetermined displacement path, the locking member being angularly displaceable between the first and second positions, which are angularly spaced from each other, in each of which the engagement formation is positioned such that a said striker element is releasably engageable therewith and between which a said striker element is held captive in the engagement formation. 
     The locking member may be pivotally/rotationally connected to the body. 
     The locking member may include a first striker element engagement formation which is configured to engage a striker element for part of its displacement relative to the locking arrangement along a predetermined displacement path in a first displacement direction, wherein the locking member is configured to be displaced relative to the body, when the first engagement formation engages with the striker element and as the striker element is displaced relative to the locking arrangement further along the predetermined displacement path in the first displacement direction, away from its first position (hereinafter referred to as the “first locked position”), the locking member also including a second striker element engagement formation, which is either separate from, or forms part of, the first striker element engagement formation, the second engagement formation being configured to engage the striker element for part of its displacement relative to the locking arrangement along the predetermined displacement path in a second displacement direction, wherein the locking element is configured to be displaced relative to the body, when the second engagement formation engages with the striker element and as the striker element is displaced relative to locking arrangement further along the displacement path in the second displacement direction, away from its second position (hereinafter referred to as the “second locked position”). 
     The first and second engagement formations may be oppositely disposed relative to each other. 
     The first and second striker element engagement formations may be oppositely disposed relative to each other. 
     The locking arrangement may include a locating/limiting mechanism which is engageable with the locking member, at least at some stage, during displacement of the locking member relative to the body in order to limit the amount of relative displacement between the locking member and the body. More specifically, the limiting mechanism may be configured to limit the amount of displacement of the locking member, relative to the body, away from its first locked position. The locking arrangement may include a shaft which is rotatably mounted to the body and to which the locking member is connected such that rotation of the shaft causes rotation of the locking member. The limiting mechanism may include a first limiting member which is rotatably fitted over the shaft and rotatable relative to the body, and a second limiting member which projects/protrudes radially outwardly from the shaft and which is engageable with the first limiting member, at least at some stage, during the displacement of the locking member between its first and second locked positions, in order to limit the amount of relative displacement between the locking member and the body. The limiting mechanism may include a securing element which is configured to secure and fix the first limiting member releasably relative to the body. The securing element may be a type of fastening means such as a screw. The second limiting member may include a stub formation. 
     The first limiting member may define a recess/cavity which extends along a circumference of the shaft and in which at least part of the second limiting member is located, the recess/cavity defining a path (hereinafter referred to as “path A”) along which the at least part of the second limiting member is displaceable, when the shaft is rotated relative to the first limiting member. The cavity/recess may extend along a circumference of the shaft. 
     A limiting formation may be located at at least one end, preferably both ends, of path A, in order to limit the amount by which the second limiting member (and shaft) can be displaced along path A, by engaging with the second limiting member when it reaches the corresponding end of path A. The first limiting member may have an annular disk-shaped body which defines an inner, elongate cut-out which, when the first limiting member is fitted over the shaft, extends along a circumference of the shaft and defines path A. 
     The locking arrangement may include a securing mechanism which is configured to secure the locking member releasably in the first locked position and/or the second locked position. The securing mechanism may include a securing member which is displaceable relative to the locking member between a secured position where the securing member secures, or releasably secures, the locking member relative to the body in the first and/or second locked positions and an unsecured position where the locking member is allowed to be displaced relative to the body. More specifically, when the securing member is in its secured position, it may releasably secure the locking member relative to the body in the first locked position and/or the second locked position, and the securing mechanism may include a fixing member which is displaceable relative to the securing member between a fixed position wherein the fixing member fixes the securing member in its secured position and a free position wherein the securing member is allowed to be displaced to its unsecured position. More specifically, the fixing member may be displaceable into engagement with the securing member for fixing the securing member in its secured position, thereby locking the locking member in its first locked position and/or its second locked position; and out of engagement with the securing member for allowing the securing member to be displaced to its unsecured position. The fixing member may be connected to an actuator or displacement arrangement, which may include a solenoid, which is configured to displace the fixing member out of engagement with the securing member from its fixed position towards its free position. The fixing member may be connected to the actuator via a lever. The lever may be a first order lever, wherein the fixing member and actuator are connected to the lever on opposite sides of a pivotal connection via which the lever is connected to the body or part of the locking arrangement which is fixed relative to the body. The fixing member may therefore be connected to one end of the lever and the actuator may be connected to an opposite end of the lever. A displacement path (hereinafter referred to as “path B”) of the fixing member as it is displaced into and out of engagement with the securing member may be substantially parallel to a displacement path (hereinafter referred to as “path C”) of the actuator as it actuates and displaces the fixing member. The fixing member and an actuator arm of the actuator may be substantially of the same (or similar) weight. The fixing member may be a lock pin. 
     The securing member may be configured to engage with a corresponding third engagement formation of the locking member, when the securing member is in its secured position. The securing mechanism may include a biasing means which is configured to bias the securing member towards its secured position. The securing member, when in its secured position, may extend, at least partially, into a recess or opening provided by the third engagement formation, the securing member therefore engaging with a wall(s)/surface(s) of the third engagement formation defining the recess or opening, and wherein the locking arrangement may be configured such that when the locking member is in its first or second locked position, the securing member is in register with the recess or opening of the third engagement formation, thereby allowing the securing member to extend into the recess or opening in order to secure the locking member releasably in its first or second locked position. 
     The wall(s)/surface(s) of the third engagement formation defining the recess or opening may taper as it leads into the locking member such that when the securing member is in its secured position and a sufficient amount of force/torque is applied to the locking member away from the first or second locked position, relative to the body, the securing member is urged towards its unsecured position as a result of the force acting thereon by the wall(s)/surface(s), against the bias of the biasing means. Therefore, when the securing member is in its secured position, it releasably secures the locking member in its first and/or second locked position, however, once a sufficient amount of force or torque is applied to the locking member, the locking member can be displaced out of its first and/or second locked position. However, when the securing mechanism includes a fixing member, and the fixing member is in its fixed position, the locking member is fixed in its locked position (be it the first or second locked position) and a force/torque applied to the locking member will therefore not force the securing formation into its unsecured position. 
     The first engagement formation may be configured to be displaceable in a plane as the locking member is displaced towards, or away from, its first locked position, and the securing member may be configured to be displaceable relative to the locking member along a securing path, which is oriented transverse to the said plane, between its secured and unsecured positions. More specifically, the securing path may be oriented substantially perpendicular to the plane. Alternatively, the first engagement formation may be configured to be displaceable generally in a plane as the locking member is displaced towards, or away from, its first locked position, and the securing member may be configured to be displaceable relative to the locking member along a securing path, which is oriented substantially parallel to the said plane, between its secured and unsecured positions. 
     Preferably, the locking member may be displaceable between its first and second locked positions and the locking member may therefore the third engagement formation with which the securing member engages when the locking member is in its first locked position and the securing member is in its secured position; and a fourth engagement formation with which the securing member engages when the locking member is in its second locked position and the securing member is in its secured position. The fourth engagement formation may be similar to the third engagement formation and may therefore have a recess or opening into which the securing member extends, at least partially, when the locking member is in its second locked position and the securing member is in its secured position, thereby engaging with a wall(s)/surface(s) of the fourth engagement formation defining the recess or opening. The locking arrangement may be configured such that when the locking member is in its second locked position, the securing member is in register with the recess or opening of the fourth engagement formation, thereby allowing the securing member to extend into the recess or opening in order to secure the locking member releasably in its second locked position. The locking arrangement may, in this case, include an insert which is insertable into one of the recesses of the third or fourth engagement formation for inhibiting the securing member from extending into the particular recess and therefore inhibiting the securing formation from securing the locking member into the particular locked position, be it the first or second locked position. 
     The locking member may include a first locking member element which defines the third and/or fourth engagement formations; and a second locking member element, which is connected to, but spaced from, the first locking member element, and which defines the first and second engagement formations. The first and second locking member elements may be interconnected by means of a shaft such that rotation of the shaft causes both locking member elements to rotate, the locking member elements therefore being angularly/rotationally displaceable relative to the body about an axis of rotation defined by the shaft. 
     The locking arrangement may be configured to engage with a second striker element to thereby create a type of dual-locking arrangement. The locking member may therefore include a third locking member element, which is configured in a similar fashion to the second locking member element, the third locking member element therefore including two engagement formations, namely a fourth and fifth engagement formation, which are configured to engage with a second striker element in a similar fashion to the first and second engagement formations located on the second locking member element. The third locking member element may be connected to the first and second locking member elements by means of the shaft. 
     In an alternative embodiment, the locking member may be slidably displaceable relative to the body, towards and away from, a first locked position. The locking member may be biased by a biasing means towards its first locked position. When in the first locked position, the first and/or second engagement formations of the locking member may be positioned in the displacement path (i.e. the relative displacement path between the locking arrangement and the striker element) and may therefore be configured to engage, at some stage, with a striker element when, in use, the locking arrangement and striker element are displaced relative to each other along the displacement path. When the striker element engages with the first or second engagement formation and is displaced further along the displacement path, the locking member is urged/forced, against the bias of the biasing means, away from its first locked position to thereby allow the striker element to pass. Once passed, the biasing means will return the locking member to its first locked position. 
     In accordance with another aspect of the invention there is provided a lock installation which includes:
         a support structure which defines an access opening through which access is in use granted to an access-restricted enclosure;       

     a door which is displaceably mounted to the support structure and which is displaceable between a closed position in which the door closes off the access opening in order to prohibit access to the access-restricted enclosure, and an open position where the access opening is not closed off by the door, thereby providing access to the access-restricted enclosure through the access opening; 
     a locking arrangement which is mounted to one of the door and the support member; and 
     a striker element which is mounted to the other of the door and the support member, the locking arrangement and striker element therefore being displaceable relative to each other along a predetermined displacement path when the door is displaced between its open and its closed positions, wherein the locking arrangement includes
         a body,   a locking member which is displaceable relative to the body, the locking member defining at least one striker element engagement formation which is configured to engage the striker element for part of its displacement along the predetermined displacement path as the door is displaced relative to the support structure, the locking member being displaceable between first and second spaced apart positions in each of which the engagement formation is positioned such that the striker element is releasably engageable therewith and between which the striker element is in engagement with the engagement formation, and   a securing mechanism configured to secure the locking member releasably in at least one of the first and second spaced apart positions.       

     The locking member may be configured to allow the striker element to be spaced from, and therefore not in constant engagement with, the striker element engagement formation, when the locking member is in its first and/or second positions. The striker element may be displaceable between two extremities along its predetermined displacement path and the locking member may be configured to allow the striker element to be spaced from the striker element engagement formation when in one of its two extremities and only to engage with the striker element engagement formation when the striker element is displaced between its two extremities. 
     The locking arrangement may be a locking arrangement as defined above. 
     In accordance with a further aspect of the invention there is provided an access control system which includes: 
     a locking arrangement as defined above; and 
     a control unit which is connected to the locking arrangement and which is configured to receive an input from a user; determine whether, based on the input received from the user, access may be granted; and if so, to grant access by communicating with the locking arrangement to allow the locking member to be displaced, relative to the body of the locking arrangement, away from its first locked position. 
     More specifically, the control unit may be configured to communicate with the actuator or displacement arrangement of the locking arrangement for displacing the lock pin out of engagement with the securing member, when access is granted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings. In the drawings: 
         FIG. 1  shows a three-dimensional view of a locking arrangement in accordance with the invention; 
         FIG. 2  shows a side view of the locking arrangement of  FIG. 1 ; 
         FIG. 3  shows a sectional side view of the locking arrangement of  FIG. 1 ; 
         FIG. 4  shows a three-dimensional exploded view of a locking member and part of an insert of the locking arrangement of  FIG. 1 ; 
         FIG. 5  shows a sectional side view of part of the locking arrangement of  FIG. 1 , where a securing member of a securing mechanism of the locking arrangement is in a secured position and a lock-pin of the securing mechanism is in a free position; 
         FIG. 6  shows a sectional side view of part of the locking arrangement of  FIG. 1  (similar to  FIG. 5 ), with the securing member in an unsecured position; 
         FIG. 7  shows a sectional side view of the locking arrangement of  FIG. 1  (similar to  FIG. 5 ), with the securing member in an unsecured position and where the insert shown in  FIG. 4  is inserted into a recess provided in the locking member; 
         FIG. 8  shows a schematic top view of the locking arrangement of  FIG. 1 , when in use, where a locking member of the locking arrangement is in a first locked position; 
         FIG. 9  shows a schematic top view of the locking arrangement of  FIG. 1 , when in use, where a locking member of the locking arrangement is in a second locked position; 
         FIG. 10  shows a schematic lay-out of an access control system in accordance with the invention; 
         FIG. 11  shows a flow diagram of the access control system of  FIG. 10 ; 
         FIG. 12  shows a three-dimensional view of part of the locking arrangement of  FIG. 1 , when in use, where the locking arrangement has a dual locking member, with both striker elements in respective closed positions; 
         FIG. 13  shows a three-dimensional view of part of the locking arrangement of  FIG. 12 , when in use, where the locking arrangement has a dual locking member, with one striker element in a closed position and the other striker element in an open position; 
         FIG. 14  shows a three-dimensional view of part of the locking arrangement of  FIG. 12 , when in use, where the locking arrangement has a dual locking member, with both striker elements in respective open positions; 
         FIG. 15  shows a three-dimensional view of part of the locking arrangement of  FIG. 1 , when in use, where the locking arrangement has a different locking member and where the locking member is in a first locked position and a striker element is in a closed position; 
         FIG. 16  shows a three-dimensional view of part of the locking arrangement shown in  FIG. 15 , where the locking member is displaced away from its first locked position and the striker element is positioned midway between its open and closed positions; 
         FIG. 17  shows a three-dimensional view of part of the locking arrangement shown in  FIG. 15 , where the locking member is in its first locked position and the striker element is in its open position; 
         FIG. 18  shows a schematic top view of part of the locking arrangement of  FIG. 1 , when in use, where the locking arrangement has a different locking member and wherein the locking member is in a first locked position and the striker element is in a closed position; 
         FIG. 19  shows a schematic top view of part of the locking arrangement shown in  FIG. 18 , where the locking member is positioned midway between its first and second locked positions. 
         FIG. 20  shows a schematic top view of part of the locking arrangement shown in  FIG. 18 , where the locking member is positioned proximate a second locked position and the striker element is about to disengage with the locking member; 
         FIG. 21  shows a schematic top view of part of the locking arrangement shown in  FIG. 18 , where the locking member is in its second locked position and the striker element is in an open position; 
         FIG. 22  shows a sectional top view of an alternative embodiment of the locking arrangement of  FIG. 1 ; 
         FIG. 23  shows another sectional top view of the locking arrangement of  FIG. 22 ; 
         FIG. 24  shows a further sectional top view of the locking arrangement of  FIG. 22 ; 
         FIG. 25  shows a three-dimensional view of part of the locking arrangement of  FIG. 22 ; 
         FIG. 26  shows another three-dimensional view of part of the locking arrangement of  FIG. 22 ; 
         FIG. 27  shows a three-dimensional view of the locking arrangement of  FIG. 22 ; and 
         FIG. 28  shows a schematic circuit layout of the locking arrangement of  FIG. 22 ; and 
         FIG. 29  shows a front view of a lock installation in accordance with the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     In the drawings reference numeral  10  refers generally to a locking arrangement in accordance with the invention. 
     The locking arrangement  10  includes a body  12 , a locking member  14 , which is rotationally mounted to the body  12 ; and a securing mechanism  16 . 
     The locking member  14  is rotationally mounted onto the body  12  by means of a shaft  15  and bearing arrangement generally indicated by reference numeral  13  (the bearing arrangement is not illustrated in detail). The locking member  14  defines a recess or cut-out  17  (see  FIG. 4 ). Sides  19 . 1 ,  19 . 2  of the locking member  14  forming the recess  17  form first and second engagement formations  18 . 1 ,  18 . 2 , respectively, which, in use, engage with a striker element  100 . The engagement with the striker element  100  will however be discussed in more detail below. Locking member  14  includes third and fourth engagement formations  23 . 1 ,  23 . 2 . Each engagement formation  23 . 1 ,  23 . 2  defines a recess  20 . 1 ,  20 . 2 , with walls or surfaces  21 . 1 ,  21 . 2  of the locking member  14  defining the recesses  20 . 1 ,  20 . 2  tapering inwardly as they lead into the locking member  14 . The locking arrangement  10  also includes a complementary insert  24  (see  FIG. 4 ) which is receivable in either recess  20 . 1 ,  20 . 2 . The locking member  14  is rotatable relative to the body  12  about an axis of rotation  110 . The third and fourth engagement formations  20 . 1 ,  20 . 2  are at an equal radial spacing from the axis  110  and are accordingly angularly displaceable along a circular path about the axis  110 . 
     The securing mechanism  16  includes a securing member  26 , a fixing member in the form of an elongate lock pin  28 , a displacement arrangement  30  and a biasing means  32 . The securing member  26  has body  121  which can generally be divided into a circular cylindrical main body portion  122 ; a circular cylindrical operatively upper portion  125  which protrudes from an end of, and has a smaller diameter than, the main body portion  122 ; and an operatively lower portion  123  (see  FIG. 5 ) which protrudes from the lower end of the main body portion  122 . The operatively lower portion  123  of the body  121  tapers from the main body portion  122  into a downwardly projecting point. Due to the difference in diameter between the operatively upper portion  125  and the main body portion,  122 , the body  121  defines an annular flange or shoulder  40 . The body  12  defines a channel  34  within which the securing member  26  is positioned (see  FIG. 3 ). The securing member  26  is displaceable relative to the body  12  and locking member  14  along a securing path in the channel  34  which is generally parallel to the axis  110  in the direction of arrows  120 . The securing member  26  is positioned above the locking member  14  such that when the locking member  14  is rotated about the axis  110 , the recesses  20 . 1 ,  20 . 2  of the third and fourth engagement formations  23 . 1 ,  23 . 2  will, at some stage, come into register, or in line, with the securing member  26 . The securing member  26  is biased by the biasing means  32  (which may be in the form of a spring) towards the locking member  14 . Therefore, when the securing member  26  is in register with the recesses  20 . 1 ,  20 . 2  of the third or fourth engagement formations  23 . 1 ,  23 . 2 , the biasing means  32  will urge the securing member  26  to extend into the recesses  20 . 1 ,  20 . 2  (more particularly the operatively lower portion  123  of the body  121  of the securing member  26 ), thereby inhibiting further rotation of the locking member  14  about the axis  110 . 
     The securing member  26  is therefore displaceable along the channel  34  between an unsecured position (shown in  FIG. 6 ) where the securing member  26  merely abuts an upper surface  38  of the locking member  14  and allows the locking member  14  to be rotated about the axis  110 ; and a secured position (shown in  FIGS. 3 and 5 ) where the locking member  26  extends into one of the recesses  20 . 1 ,  20 . 2  of the third or fourth engagement formations  20 . 1 ,  20 . 2 , thereby inhibiting rotation of the locking member  14  about the axis  110 . The securing member  26  is therefore configured to secure the locking member  14  releasably into either a first locked position (see  FIG. 8 ) where the securing member  26  extends into the recess  20 . 1  of the third engagement formation  23 . 1 ; or a second locked position (see  FIG. 9 ) where the securing member  26  extends into the recess  20 . 2  of the fourth engagement arrangement  23 . 2  (the fact that the locking member  14  is only releasably secured in one of its locked positions by the securing member  26  will be explained below). 
     The tapered surfaces  21 . 1 ,  21 . 2  of the locking member  14  defining the recesses  20 . 1 ,  20 . 2  of the third and fourth engagement formations  23 . 1 ,  23 . 2  and a complementary tapered surface of the operatively lower portion  123  of the securing member  26  function as a detent or cam arrangement. Accordingly, when a sufficient amount of angular force or torque is applied to the locking member  14 , relative to the body  12  (about the axis  110 ), the securing member  26  is urged upwards towards its unsecured position, against the bias of the biasing means  32 , due to the force(s) acting thereon by the tapered surfaces  21 . 1 ,  21 . 2  in the manner of a cam and follower. The securing member  26  therefore only releasably secures the locking member  14  into its first and second locked positions. 
     The lock pin  28  is displaceable into and out of engagement with the shoulder  40  of the securing member  26 . More specifically, when the securing member  26  is in its unsecured position (see  FIGS. 6 and 7 ), an end portion of the lock pin  28  abuts a side  27  of the main body portion  122  of the securing member  26  and is therefore disengaged from the shoulder  40 . However, when the securing member is in its secured position (see  FIGS. 3 and 5 ), the lock pin  28  can be slid into engagement with the shoulder  40 , thereby inhibiting the securing member  26  from being displaced towards its unsecured position when an angular force or torque is applied to the locking member  14 . The lock pin  28  is therefore displaceable relative to the securing member  26  between a fixed or locked position (see  FIG. 3 ) where the lock pin  28  engages with the shoulder  40  of the securing member  26  and a free or unlocked position where the lock pin  28  is disengaged from the shoulder  40  (see  FIGS. 5 to 7 ). The lock pin  28  is displaceable between its two positions by means of an actuator or displacement arrangement  30 , which in this example includes a solenoid  37 , to which it is connected. More specifically, the lock pin  28  is longitudinally aligned with an actuating/displacement path of the actuator or displacement arrangement  30 . The solenoid  37  only requires about 300 mA to be operated and is controlled by a control unit which will be described in more detail below. Therefore, although the securing member  26 , along with the biasing means  32 , only releasably secures the locking member  14  into one of its two locked positions, the lock pin  28  can fix the securing member  14  into its secured position, thereby fixing or locking the locking member  14  into one of its locked positions. In this example, the locking arrangement  10  also includes a manual/mechanical override mechanism  71  which is also configured to displace the lock pin  28  between its two positions. The override mechanism  71  includes a stem  73  which is rotatable about an axis of rotation  131 . An end portion  75  of the stem  73  is configured to engage with a transverse rod  77  which is in turn connected to the lock pin  28 , such that the lock pin  28  is displaceable between its two positions upon rotation of the stem  73 . Although not specifically shown, the override mechanism  71  may include a key formation for receiving a key, wherein the key formation is configured to inhibit rotation of the stem  73  unless an appropriate key is inserted into the key formation. 
     In use, the locking arrangement  10  may form part of an access control system  200  (see  FIG. 10 ) for restricting access to an access-restricted area. The system  200  includes a lock installation which includes the locking arrangement  10  which is mounted to a door frame (not shown); and a corresponding striker element  100  (see  FIGS. 8 and 9 ) which is mounted to, or forms part of, a corresponding door which is hingedly or slidably connected to the door frame (not specifically shown). The system further includes a control unit  202  which is configured to actuate the actuator or displacement arrangement  30 ; and a user input arrangement such as a card reader  204  which is connected to the control unit  202  (in an alternative embodiment, the locking arrangement  10  may be mounted to the door and the striker element  100  can be mounted to the door frame). The striker element  100  is displaceable relative to the locking arrangement  10  along a displacement path  113  (or vice versa) between two extremities, e.g. a closed position (see  FIG. 8 ) and an open position (see  FIG. 9 ), and the striker element  100  is receivable within the recess  17  of the locking member  14  for displacement of the striker element  100  between its two extremities. In both extremities (i.e. the closed and open positions), the striker element  100  is spaced from the recess  17 , i.e. the locking member  14  is not in constant engagement with the striker element  100  during use, but only engages therewith when the striker element  100  is displaced along its displacement path  113  between its two extremities. The locking arrangement  10  therefore does not physically lock the striker element  100  in its closed and open positions but merely allows or prevents the displacement of the striker element  100  between its two positions. As shown in  FIG. 8 , the locking member  14  may be positioned in the first locked position, with the securing member  26  in its secured position and the lock pin  28  in its fixed position. In this configuration, the first engagement formation  18 . 1  inhibits the striker element  100 , and therefore the door, from being displaced in a first displacement direction  222  along the displacement path  113 . 
     The card reader  204  is configured to read identification cards of users and to send the details thereof to the control unit  202  (see  FIG. 11 , block  300 ). Upon receipt of the details the control unit  202  determines whether or not access may be granted (see  FIG. 11 , block  302 ). If access is granted, the control unit  202  instructs the displacement arrangement  30  to displace the lock pin  28  into its free position (see  FIG. 11 , block  304 ) for a certain predetermined time period (e.g. 5 seconds) (see  FIG. 11 , block  306 ) whereafter the displacement arrangement  30  will again be instructed by the control unit  202  to displace the lock pin  28  towards its fixed position (see  FIG. 11 , block  308 ). When a user, within the said period, then applies a sufficient amount of force/torque on the striker element  100 , e.g. by pushing on the door, to move it in the first displacement direction  222 , the striker element  100  will engage with the first engagement formation  18 . 1  and transfer the force/torque to the locking member  14 , thereby displacing the securing member  26  upwards against the bias of the biasing means  32  towards its unsecured position, thereby allowing the locking member  14  to be displaced from its first locked position shown in  FIG. 8  towards its second locked position shown in  FIG. 9 . When the locking member  14  has been displaced into its second locked position, the securing member  26  is again displaced towards its secured position (i.e. into the recess  20 . 2 ) and the lock pin  28  is displaced into its fixed position (after the time delay), thereby locking the locking member  14  into its second locked position. 
     Similarly, when the user wants to exit the restricted access area, the lock pin  28  may be disengaged from the securing member  26  via another card reader (not shown) which is positioned inside the access restricted area. With the lock pin  28  in its free position, the user may again push the door (in the opposite direction) which will cause the striker element  100  to engage with the second engagement formation  19 . 2 , thereby displacing the locking member  14  towards its first locked position. 
     The locking arrangement  10  need not necessarily form part of a sophisticated access control system  200  but may also be operated by a simple switch. 
     By inserting an insert  24  into one of the recesses  20 . 1 ,  20 . 2  of the third or fourth engagement formations  23 . 1 ,  23 . 2 , the locking arrangement  10  can be configured to be lockable in only one position, i.e. by inhibiting the securing member  26  from extending into a particular recess  20 . 1 ,  20 . 2  of one of the engagement formations  23 . 1 ,  23 . 2 , the locking member  14  is inhibited from being locked into one of the two locked positions (see  FIG. 7 ). In an alternative embodiment, where a locking arrangement  100  with only one lockable position is required, the locking member  14  may include only a third (and not a fourth) engagement formation  23 . 1  (and recess  20 . 1 ). 
     If the locking member  14  constantly engages with the striker element  100 , forces acting on the locking member by the striker element  100  (e.g. as a result of a door seal or a person pressing on the door) may end up being transferred to the securing member  26  which in turn may press against the lock pin  28 . The lock pin  28  may therefore as a result require more force to be operated in order to disengage from the securing member  26 , which would mean the use of a larger solenoid (which will draw larger current). 
     However, by using the locking arrangement  10  set out above, this problem is alleviated by the fact that the striker element  100  is disengaged from the locking member  14  when in its closed or open position. The lock pin  28  will therefore require less force to be operated which, in turn, means the use of a smaller solenoid. 
       FIGS. 12 to 21  illustrate alternative embodiments of the locking member  14  and, unless otherwise indicated, the same reference numerals used in  FIGS. 1 to 9  will be used to designate similar components in  FIGS. 12 to 21 . 
     In  FIGS. 12 to 14  the locking member  14  includes first, second and third locking member elements  61 . 1 ,  61 . 2 ,  61 . 3 . The locking member elements  61 . 1 ,  61 . 2 ,  61 . 3  include circular disc shaped bodies  102 . 1 ,  102 . 2 ,  102 . 3  and are interconnected by means of a central shaft  15  which is configured to rotate the locking member elements  61 . 1 ,  61 . 2 ,  61 . 3  in unison about the axis of rotation  110 . 
     The first locking member element  61 . 1  includes third, fourth and fifth engagement formations which are in the form of three angularly spaced recesses  92 . 1 ,  92 . 2 ,  92 . 3  which lead into the body  102 . 1  of the first locking member element  61 . 1  from a radially outer side thereof. The securing member  26  is positioned on the radially outer side of the first locking member element  61 . 1  such that when the locking member  14  is rotated about the axis  110 , the recesses  92 . 1 ,  92 . 2 ,  92 . 3  of the third, fourth and fifth engagement formations will, at some stage, come into register, or in line, with the securing member  26 . 
     The second and third locking member elements  61 . 2 ,  61 . 3  each defines two angularly spaced recesses  63 . 1 ,  63 . 2 ,  65 . 1 ,  65 . 2  which are similar to the recess  17  shown in  FIG. 4 . Although not specifically indicated, the recesses  63 . 1 ,  63 . 2 ,  65 . 1 ,  65 . 2  each defines engagement formations for engaging with a corresponding striker element. The purpose of having both a second and a third locking member element  61 . 2 ,  61 . 3 , each having two recesses  63 . 1 ,  63 . 2 ,  65 . 1 ,  65 . 2 , is to allow the locking arrangement  10  to accommodate two striker elements  100 . 1 ,  100 . 2  (i.e. two doors). In other words, the locking arrangement  10  is configured to control access through two doors.  FIG. 12  shows the two striker elements  100 . 1 ,  100 . 2  in their respective closed positions, with the recesses  63 . 1 ,  65 . 1  of the second and third locking member elements  61 . 2 ,  61 . 3  being positioned in the displacement path of the striker elements  100 . 1 ,  100 . 2 . 
     When, for instance, striker element  100 . 2  is displaced towards its open position, it engages the recess  65 . 1  and as a result rotates the third locking member element  61 . 3  (assuming that the lock pin  28  is in its free or unlocked position and a sufficient amount of force is applied to the third locking member element  61 . 3  to displace the securing member  26  towards its unlocked position) which causes the first and second locking member elements  61 . 1 ,  61 . 2  also to rotate to a position shown in  FIG. 13 . In this position, the recess  63 . 2  (and not the recess  63 . 1 ) is in the displacement path of the striker element  100 . 1 . If the striker element  100 . 1  is now displaced towards its open position, it will engage the recess  63 . 2  and as a result rotate the second locking member element  61 . 2  which will cause the first and third locking member elements  61 . 1 ,  61 . 3  to also rotate to a position shown in  FIG. 14 . 
     In  FIGS. 15 to 17  the locking member  14  is slidably displaceable relative to the body  12 , along a path generally indicated by reference numeral  150 , between a locked position (shown in  FIGS. 15 and 17 ) and an unlocked position (shown in  FIG. 16 ). The locking member  14  defines a channel  79 , having tapered sides, within which the securing member  26  can extend to lock the locking member  14  in its locked position. The locking member  14  is biased towards a locked position by a biasing means (not shown) which acts on one end  87  of the locking member  14 . An opposite end of the locking member  14  has two inclined surfaces  89 ,  91  which act as engagement formations for engaging with a striker element  100 . When the locking member  14  is in its locked position and the striker element  100  is in its closed position (see  FIG. 15 ), the inclined surface  89  is positioned in the displacement path of the striker element  100 . When the striker element  100  is displaced towards its open position, it engages with the surface  89 , which causes the locking member to be displaced towards its unlocked position (see  FIG. 16 ) against the bias of the biasing means which, in turn, causes the securing member  26  to be urged towards its unsecured position. Once the striker element  100  has passed the locking member  14 , the biasing means will displace the locking member  14  back into its locked position (see  FIG. 17 ). In this position, the surface  91  is now in the displacement path of the striker element  100 . 
     In  FIGS. 18 to 21  the locking member  14  has a circular disc shaped body  141  which is rotatable relative to the body  12  of the locking arrangement  10  (not specifically shown) about an axis of rotation  110 . A finger shaped formation  142  projects radially outwardly from the body  141 . The formation  142  defines first and second engagement formations  19 . 1 ,  19 . 2  which, in use, are positioned in the displacement path of a striker element  100 . The locking member  14  defines two angularly spaced slots  144 . 1 ,  144 . 2  within which the securing member  26  is receivable for locking the locking member  14  releasably in its first and second locked positions. The body  141  of the locking member  14  defines a small hole  145  which is located midway between the two slots  144 . 1 ,  144 . 2 , proximate a radially outer side of the body  141 . A biasing means (e.g. a spring; not specifically shown) is connected between the locking member  14 , by extending through the hole  145 , and a post/bar  146  which is connected to the body  12  (not specifically shown). The purpose of the biasing means is to bias the locking member  14  towards a neutral position such that after the striker element  100  has displaced the locking member  14  out of its displacement path during use (see  FIG. 20 ), the biasing means will urge the locking member  14  back towards its first or second locked position shown in  FIGS. 18 and 21 . 
       FIGS. 22 to 28  illustrate another embodiment of the locking arrangement  10 , whereas  FIG. 29  illustrates a lock installation  400  which incorporates the locking arrangement  10 . Again, unless otherwise indicated, the same reference numerals used in  FIGS. 1 to 9  will be used to designate similar components in  FIGS. 22 to 27 . 
     In this embodiment, the locking member  14  is mounted on a thick shaft  15  such that rotation of the shaft  15  about an axis  110  causes rotation of the locking member  14  (see  FIG. 26 ). The shaft  15  defines a recess  93  which leads into a body of the shaft  15  from a radially outer side thereof (see  FIG. 24 ) into which a locking member  26 , which is positioned on a radially outer side of the shaft  15 , is receivable. The specific configuration between the securing member  26  and the shaft  15  (and recess  93 ), in this embodiment, is similar to the configuration between the securing member  26  and locking member element  61 . 1  (and its recesses  92 . 1 - 92 . 3 ) illustrated in  FIG. 14 . 
     The locking arrangement  10  includes a first order lever  109  which is pivotally connected to the body  12  via a pivotal connection  111 . One end of the lever  109  is connected to an actuator arm  113  of the displacement arrangement  30 , while the other end of the lever  109  is connected to the lock pin  28  which is generally thicker than the lock pin  28  illustrated in  FIG. 3 . The displacement arrangement  30  and lock pin  28  are arranged such that an actuating path  115  of the actuator arm  113  is spaced from, and parallel to, a displacement path  117  of the lock pin  28  as it travels into and out of engagement with a shoulder  40  of the securing member  26 . The lock pin  28  and actuator arm  113  are substantially of the same weight. 
     If the locking arrangement  10  illustrated in  FIGS. 1 to 9  is subjected to excessive vibrations, the lock pin  28  might, in certain cases, disengage from the shoulder  40  (and allow the securing member  26  to be displaced towards its unsecured position). This is due to the fact that the lock pin  28  is longitudinally/linearly aligned with an actuating path of the actuator or displacement arrangement  30  and is connected thereto. If therefore the lock pin  28  (when in its locked position) and an actuator arm of the actuator  30  are subjected to a vibrational force which urges them along the actuating path away from the locked position of the lock pin  28 , then these forces will, in a sense, be combined and if the combined force is large enough, may end up temporarily displacing the lock pin  28  out of engagement with the shoulder  40 . However, in the embodiment illustrated in  FIGS. 22 to 27 , the lever  109  counters the respective vibrational forces which the actuator arm  113  and the securing member  26  may be subjected to. More specifically, since the actuating path  115  and displacement path  117  are parallel to each other, vibrational forces which act on the actuator arm  113  and the securing member  26  will tend to urge them in the same direction along their respective paths  115 ,  117 . However, since the actuator arm  113  and the securing member  26  are connected to the respective ends of a first order lever  109 , the lever  109  will cause the respective vibrational forces acting on the actuator arm  113  and the securing member  26  (in the same direction) to work against each other (i.e. cancelling each other out). This is further aided by the fact that the lock pin  28  and actuator arm  113  are similar in weight. 
     The locking arrangement  10  includes a switch arrangement  127  which is configured to operate an operating light such as an LED  129  and which is operatively connected to the displacement arrangement  30  such that when the displacement arrangement  30  displaces the lock pin  28  out of engagement with the shoulder  40  (i.e. into its unlocked position), it causes the switch arrangement  127  to power the LED  129 . 
     An operating device  201  can be used, to operate the locking arrangement  10  in a key-like fashion (see  FIG. 28 ). More specifically, the locking arrangement  10  includes an operating socket or receiving device  203  which is configured to receive and cooperate with the operating device  201 . The operating device  201  includes a power source  205  (e.g. a battery) which is configured to provide power to the receiving device  203  which, in turn, is configured to transfer at least some of the power received from the power source  205  to the solenoid  37 , which forms part of an electric circuit  207 , when the correct operating device  201  is inserted. The LED  129  forms part of the circuit  207  and is connected thereto via the switch arrangement  127 . 
     When the solenoid  37  is not powered, the actuator arm  113  is locked in an extended/erect position. As a result, the lever  109  urges/forces the lock pin  28  into its locked position. When the correct operating device  201  is inserted into the receiving device  203 , the receiving device  203  establishes (e.g. by means of a switch) an electrical connection between the power source  205  and the solenoid  37 . As soon as the solenoid  37  is powered, it displaces the actuator arm  113  from its extended/erect position towards a retracted position (i.e. the actuator arm  113  is displaced in the direction of arrow  133  along the displacement path  115 ). As a result, the lever  109  urges/forces the lock pin  28  out of engagement with the shoulder  40  of the securing mechanism  16  into its unlocked position, thereby allowing the locking member  14  to rotate (e.g. to open a door to which the locking arrangement  10  is mounted) by applying a sufficient amount of torque/rotational force on the shaft  15  and locking member  14  (as described earlier in the specification). The actuator arm  113  is operatively connected to the switch arrangement  127  such that when the actuator arm  113  is in its extended/erect position, a switch  189  of the switch arrangement  127  is in an open condition (i.e. the LED  129  is disconnected from the circuit  207 ) and when the actuator arm  113  is displaced towards its retracted position, to switch the switch  189  to a closed condition, thereby connecting the LED  129  to the circuit  207  (and power source  205 ). 
     The locking arrangement  10  defines a light transmitting rod  139  which extends from the LED  129  towards an outer side of the body  12  and which is configured to channel the light from the LED  129  towards the outside, which can then be viewed by an operator. The light from the LED  129  will therefore be indicative that the correct operating device  201  has been inserted into the receiving device  203  and that the locking pin  28  is in its unlocked position. 
     From the above, it is clear that the locking arrangement  10  does not require a power source to ensure that a door to which the locking arrangement  10  is mounted remains locked. The locking arrangement  10  in fact only requires power in order to unlock the locking pin  28  of the locking arrangement  10 . (The operating device  201 , receiving device  203  and circuit  207  can also be implemented in the other embodiments of the locking arrangement  10  described above.) 
     The locking arrangement  10  further includes a limiting mechanism  191  which is configured to limit the amount of rotation of the locking member  14  and shaft  15  relative to the body  12 . More specifically, the limiting mechanism  191  is configured to help preserve/maintain the relative rotational position of the locking member  14  relative to the body  12 , when the locking member  14  has been displaced into a fully open position. The limiting mechanism  191  includes a first limiting member  143  which has an annular disk-shaped body  171  which is rotatably fitted over the shaft  15  and which is rotatable relative to the body  12 . The limiting mechanism  191  also includes a second limiting member in the form of a stub formation  149  which projects/protrudes radially outwardly from the shaft  15 . 
     The first limiting member  143  defines an inner, elongate cut-out  147  which, when the first limiting member  143  is fitted over the shaft  15 , extends along a circumference of the shaft  15 . The cut-out  147  defines a path  151 . The stub formation  149  is located in the cut-out  147  and can therefore move along the displacement path  151  as the shaft  15  (and locking member  14 ) is rotated relative to the first limiting member  143 . The limiting mechanism  191  further includes a securing element in the form of a screw which can be used to secure the first limiting member  143  to the body  12  in a specific relative rotational position. 
     The relative rotational position can be determined by displacing the striker element  100  along its displacement path from a closed position towards an open position such that it, at some stage, engages with the locking member  14  by extending into the recess  17  (which is positioned in the displacement path of the striker element  100 ) and rotates the locking member  14  (as well as the shaft  15 ) until the striker element  100  disengages from the locking member  14  (more specifically the recess  17 ). When the locking member  14  is in this position it is in a fully open position. As the locking member  14  is rotated towards its fully open position, the securing member  26  will at some stage be displaced out of its secured position inside the recess  93  and into its unsecured position where it abuts a radially outer surface  181  of the shaft  15 . As the shaft  15  rotates, a portion  161  of the body  171 , which defines one of the ends of the path  151 , engages, at some stage, with the stub formation  149 , which causes the first limiting member  143  to rotate together with the shaft  15 . When the locking member  14  has been rotated into its fully open position, the screw is inserted via an access hole  155  in order to engage frictionally with an annular surface  157  of the body  171  to thereby prevent relative rotation between the first limiting member  143  and the body  12  in the same direction. The screw, when inserted, is oriented generally perpendicular to a plane in which the annular surface  157  extends. The insertion of the screw is conducted during the installation of the locking arrangement  10 . 
     If, when in its fully open position, the locking member  14  is inadvertently rotated back towards a closed position such that the recess  17  is displaced out of register with the displacement path of the striker element  100 , then the striker element  100 , when displaced back along its displacement path towards its closed position, will engage a radially outer side  199  of the locking member  14  instead of the recess  17 . In order to correct the rotational position of the locking member  14  it can merely be rotated manually (relative to the body  12 ) towards its fully open position until the locking member  14  cannot rotate any further as a result of the screw and the portion  161  which engages with the stub formation  149 , which prevent further rotation in the same direction. When the locking member  14  reaches this position, it will be in its fully open position and the recess  17  will be in register with the displacement path of the striker element  100 . The screw, together with the portion  161  and stub formation  149 , also helps prevent the locking member  14  from being inadvertent rotated past its fully open position. 
     The lock installation  400  illustrated in  FIG. 29  includes a support structure, which in this example is a door frame  402 , a door  404  which is hingedly mounted to the door frame  402 , a locking arrangement  10  which is mounted to the door frame  402  by means of a mounting structure  403  and a striker element  100  which is mounted to the door  404  by means of a mounting structure  406 . 
     The door frame  402  defines an access opening  408  through which access is granted to an access-restricted enclosure/area of which the door  404  and door frame  402  form part of. The door  404  is hingedly displaceable relative to the door frame  402  between a closed position in which the door  404  closes off the access opening  408  in order to prohibit access to the access-restricted enclosure/area through the access opening  408 , and an open position where the access opening  408  is not closed off by the door  404 , thereby providing access to the access-restricted enclosure/area through the access opening  408 . 
     The Inventor believes that the invention provides both a cost effective locking arrangement and access controlled system. The Inventor also believes that the locking arrangement  10  is relatively easy to install and inexpensive. The locking arrangement  10  also draws significantly less current than current electro-magnetic locks the Inventor is aware of, i.e. 300 mA versus 5 A, which is largely due to the fact that the striker element  100  is not in constant engagement with the locking member  14 . 
     A further advantage of this invention is the fact that in the embodiment illustrated in  FIGS. 22 to 28 , the locking arrangement  10  only requires power in order to unlock the locking pin  28 .