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FIELD OF THE INVENTION 
       [0001]    This invention relates to locks and seals for containers, in particular those including an automatic self-checking and warning system against tampering. 
       BACKGROUND OF THE INVENTION 
       [0002]    U.S. Pat. No. 4,262,284 discloses self-monitoring seals having fiber optic bundle loops with ends mounted in stressed tamper resistant containers, the seal being formed as a padlock with a shackle and display. A battery operates microelectronics to send coded light pulse sequences through the optic loop and to show a predetermined sequence on the display. Tampering with the container or interrupting or changing the light transmission through the fiber optic bundle disrupts the predetermined display sequence. 
         [0003]    U.S. Pat. No. 4,322,721 discloses a self-checking warning or alarm installation containing an optical conductor or guide (optical fiber) as a signal line. The optical conductor together with an electronic monitoring circuit forms a free-running opto-electronic oscillator which comes to standstill when the oscillating optical signal is interrupted. An alarm or warning circuit associated with the monitoring circuit generates an alarm signal when this happens. The signal line may be of two parts, with light converter between them. The two parts may have aligned end faces such that the optical signal is interrupted upon misalignment. 
         [0004]    U.S. Pat. No. 6,420,971 describes an electronic seal comprising a housing and a loop of optical fiber in an elongated closure member connectable at both of its ends to the housing. A sensor assembly is provided for sensing integrity of the optical fiber. Hence tampering with the seal can be detected. The optical path may include an air gap between the fiber end and the sensor so that opening of the seal may be also detected. 
         [0005]    U.S. Pat. No. 4,546,345 discloses a lock with steel wire cable having an optical fiber (loop) inside the cable, which detects breaking of the cable (of the optical loop) and sounds an alarm when the cable is broken. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with the present invention, there is provided a lock for locking a closure on a container, comprising a first member and a second member movable relative to one another, the two members being of strong construction, the lock having a closed state with the two members engaged with each other, and an open state with the two members disengaged, wherein the lock further comprises:
       a control module with an infra-red (IR) emitter and an IR receiver;   an IR waveguide formed as an air channel carved in the body of the two members, starting at the IR emitter, ending at the IR receiver and passing through both members such that an IR pulse emitted by the IR emitter can pass through the waveguide and be received by the IR receiver only when the lock is in the closed state.       
 
         [0009]    Preferably, the lock members are made of steel and the channel is machined therein. Preferably, the channel passes close to the outer edges of the lock members. 
         [0010]    The control module further comprises a wireless transmitter and is adapted to transmit a warning signal to an external receiver when the IR receiver fails to receive the IR pulse emitted by the IR emitter. The IR pulse is preferably automatically emitted at predetermined intervals of time, more preferably with frequency of at least 2 Hz. The IR pulse may be modulated and encoded. 
         [0011]    The lock further comprises a movable bolt adapted to assume a locking position where the bolt engages simultaneously the first and the second members in the closed state of the lock. Thereby the bolt prevents disengagement of the first and the second members. This state of the lock is defined as a locked state. 
         [0012]    Preferably, the lock further comprises a movable blocking element adapted to assume a blocking position such that the bolt cannot be removed from its locking position without destruction. 
         [0013]    In one embodiment of the lock, it further comprises a controllable drive adapted to move the blocking element to and from the blocking position. The drive may be a bi-stable solenoid. 
         [0014]    In another embodiment of the lock (seal), the bolt comprises a breakable portion. The blocking element is adapted to assume the blocking position automatically after the bolt assumes its locking position such that the bolt can be removed from the locking position only by breaking the breakable portion. 
         [0015]    Preferably, the blocking element comprises a portion of the IR waveguide formed such that the IR pulse can pass through the waveguide only in the blocked state of the lock. 
         [0016]    The lock may further comprise a third member movably engaged to the first member and mounted to an element of the container. This element assumes a closed position when the closure is locked and an open position allowing opening of the closure. The IR waveguide and the third member of the lock are configured so that when the element is moved from its closed position towards its open position, with the lock still in its closed state, the third member moves with the element and obstructs the IR waveguide preventing passing of the IR pulse. 
         [0017]    In yet another embodiment, the lock is formed as a padlock, wherein the first member is a U-shaped shackle with cylindrical ends. The shackle has an axial channel therealong with exits at the cylindrical ends, the channel constituting a part of the IR waveguide. The second member is a lock body accommodating the control module and the rest of the IR waveguide. The lock body has two recesses adapted to receive the cylindrical ends. The body and the cylindrical ends are formed so that when the ends are inserted in the recesses, the lock automatically assumes the closed state and the shackle may be released from the body only after being cut or broken into two separate parts. 
         [0018]    The cylindrical ends have taper or bevel, and each end has a notch at the inner side of the U-shape. The body has a bore intersecting the recesses and two bolts sliding therein. The bolts are biased by a spring element towards the recesses, such that when the cylindrical ends enter the recesses, the taper or bevel pushes the bolt against the spring element into the bore to allow movement of the ends into the recesses. When the notches align with the bore, the bolts jump into the notches irreversibly locking the shackle to the body. 
         [0019]    According to another aspect of the present invention, there is provided a seal for sealing a closure on a container, comprising a U-shaped shackle with cylindrical ends and a seal body having two recesses adapted to receive the cylindrical ends. The body and the cylindrical ends are formed so that when the ends are inserted in the recesses, the seal assumes an irreversibly closed state such that the shackle may be released from the body only after being cut or broken into two separate parts. The cylindrical ends have taper or bevel and a flat segment notch at the inner side of the U-shape. The body has a bore intersecting the recesses and two bolts sliding in said bore. The bolts are biased by a spring element towards the recesses, such that when the cylindrical ends enter the recesses, the taper or bevel pushes the bolt back into the bore to allow movement of the ends into the recesses. When the notches align with the bore, the bolts engage the notches, irreversibly locking said shackle to the body. As above, only when the shackle is broken into two separate parts, each part can be rotated to disengage the cylindrical end from the bolt so that the broken part may be pulled out of the body. 
         [0020]    Preferably, the U-shaped shackle has a signal conducting means disposed along the U-shape and exiting at the cylindrical ends, and the seal body has an electronic control module with an emitter and a receiver of a signal, the control module being adapted, when the seal is in its closed state, to check periodically the integrity of the seal by emitting and receiving the signal through the signal conducting means. 
         [0021]    The control module may further comprise a wireless transmitter adapted to transmit a warning signal to an external receiver when the signal receiver fails to receive the signal emitted by the signal emitter. 
         [0022]    The signal conducting means may be an insulated electric wire, an optical fiber or an air channel conductive of IR light. 
         [0023]    Preferably, the U-shaped shackle and the body are of strong construction, for example made of steel, such as steel tube. More preferably, the U-shaped shackle further comprises a plastic or rubber tube inserted in the steel tube. 
         [0024]    Within the frame of this application, “strong construction” of a lock (seal) generally means that the lock is resistant to breaking/cutting at least as much as the closure or container on which the lock is used. If the lock (seal) is formed as a padlock, then “strong construction” would mean strength of a metal body and steel shackle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which: 
           [0026]      FIG. 1A  is a schematic front view of a shipping container equipped with the lock/seal of the present invention. 
           [0027]      FIG. 1B  is a close-up of the lock/seal of  FIG. 1A ; 
           [0028]      FIG. 2A  is a bottom view of a lock of the present invention in open state; 
           [0029]      FIG. 2B  is a bottom view of the lock of  FIG. 2  in closed state; 
           [0030]      FIG. 3A  is a back view of the lock of  FIG. 1A  in blocked state; 
           [0031]      FIG. 3B  is a back view of the lock of  FIG. 1A  in unblocked state; 
           [0032]      FIG. 4A  is a back view of a seal of the present invention in closed and blocked state; 
           [0033]      FIG. 4B  is a bottom view of one arm of the seal of  FIG. 4A ; 
           [0034]      FIGS. 5A and 5B  are respectively a side and a face view of the sealing element in the seal of  FIG. 4A ; 
           [0035]      FIGS. 6A ,  6 B and  6 C are top, side and front views of a split cam for mounting the lock/seal of the present invention; 
           [0036]      FIGS. 7A and 7B  show a breakable seal with strong shackle according to a second aspect of the invention; 
           [0037]      FIGS. 8A and 8B  are sectional views of the seal of  FIG. 7  showing releasing of the shackle; and 
           [0038]      FIG. 9  is an alternative shackle for the breakable seal of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0039]    With reference to  FIG. 1A , there is shown a face view of a shipping container  1  with doors  2  and  3 . The doors are pivotable about hinges  4  and are secured in closed state by means of rods  5  engaged in braces  6 . The rods  5  have handles  7  which may be turned inward (towards the middle of the container) to disengage the rods from the braces  6  and to release the doors  2  and  3 . 
         [0040]    With reference also to  FIGS. 1B ,  2 A and  2 B, a lock  10  of the present invention comprises two arms  12  and  14  rotatably mounted on two rods  5 A and  5 B respectively. The mounting does not allow sliding of the arms down the rods  5  (see below a detailed description of the mounting). The lock  10  further comprises a movable bolt  16  with a knob  18 , residing in a bore  19  of the arm  14  and adapted to engage the arm  12 . When the bolt engages both arms, the lock  10  is in a closed state, the bolt is in locking position, and the doors  2  and  3  cannot be opened ( FIG. 2B ). When the bolt is disengaged from the arm  12 , the lock  10  is in an open state allowing the doors  2  and  3  to be opened ( FIG. 2A ). 
         [0041]    With reference also to  FIGS. 3A and 3B  showing a back view of the lock  10 , the bolt  16  has a stem  20  and a head  22  forming a shoulder above the stem. The arm  12  has a recess  24  adapted to receive the head  22  while the arm  14  has a compression spring  26  urging the bolt into the recess  24 . 
         [0042]    The lock  10  further comprises a latch  30  mounted for sliding under the shoulder of the head  22  and coupled to a bi-stable solenoid  32 . The latch  30  has a recess accommodating the stem  20 . The solenoid  32  is adapted to toggle the latch between a blocking position engaging the head  22  such that the bolt  16  cannot be removed from its locking position without destruction ( FIG. 3A ), and an unblocking position allowing the bolt  16  to be pulled by the knob  18 , and the head  22  to leave the recess  24 . 
         [0043]    The lock  10  further comprises an electronic control module  40  with an IR emitter  42 , IR receiver  44 , a wireless (RF) transmitter  46 , a coded-signal receiver  48 , other electronic circuitry, battery, etc. (not shown). An IR waveguide  50 ,  52 ,  54  is formed as a loop starting at the IR emitter  42  and ending at the IR receiver  44 . One part  50  of the waveguide passes through the arm  12  while another part  52  passes through the arm  14  and a third part  54  passes through the latch  30 . The waveguide has the form of a channel notched in the back surface of the arms  12  and  14 , and in the latch  30 . It is closed by a cover  56 ,  58  at the back of each arm  12 ,  14 . The waveguide is interrupted by air gaps  62 ,  64  between the arms  12  and  14 , air gap  65  between the latch  30  and the arm  14 , and recesses  66 ,  68 . In such places, the neighboring parts of the waveguide are aligned with each other and the channel of the waveguide approaches the arm surface at right angle so that an IR signal could pass across the air gap. Thus, when the lock  10  is in the closed state and the latch  30  is in the blocking position, an IR pulse emitted by the IR emitter  42  can pass through the waveguide  50 ,  52 ,  54  and be received by the IR receiver  44 . 
         [0044]    The operation of the lock of the present invention is as follows. Assume that initially the container  1  is with open doors  2  and  3 , the arms  12 ,  14  of the lock  10  are disengaged, the latch  30  is toggled into the unblocking position and the bolt  16  is withdrawn ( FIG. 3B ). 
         [0045]    An operator closes the doors  2  and  3 , and secures the rods  5  in the braces  6  by rotating the handles  7  to an outward position. Now the operator rotates the arms  12  and  14  towards each other to align them as shown in  FIGS. 1B and 2B . The recess  24  of the arm  12  is aligned with the bolt head  22 . The operator pushes the knob  18 , the bolt head  22  enters the recess  24 , and the shoulder of the head  22  passes over the latch  30 . 
         [0046]    Now the operator uses a coded-signal transmitter (not shown) to send an access code for locking to the coded-signal receiver  48 . The coded-signal communication may be in RF, IR, visible light, by electric contact, etc., or by vibration, as for example described in U.S. Pat. No. 6,411,195 to the same inventor. The control module  40  identifies the coded signal and operates the bi-stable solenoid  32  to toggle the latch  30  into its blocking position, as shown in  FIG. 3A . Next, the control module starts periodical emission of IR pulses. 
         [0047]    With the lock  10  in the closed state and the latch  30  in the blocking position, the waveguide parts  50 ,  52  and  54  are aligned with each other and the IR pulses are detected by the IR receiver  44 . This is the normal state of the lock. 
         [0048]    If for some reason IR pulses are not detected, the control module  40  activates the wireless transmitter  46  and sends an alert signal to a remote receiver (not shown). The remote receiver may be at the ship bridge, at a store house management room, police station, etc. 
         [0049]    One condition for missing IR pulses is an open waveguide. This may happen when the lock is broken or the arms  12  and  14  are misaligned (the lock is not in closed state); 
         [0050]    Another condition may be an interrupted waveguide. This may occur when the latch  30  is not in blocking position (see  FIG. 3B ). 
         [0051]    Thus the lock detects and reports abnormal conditions indicative of attempts to break into the container, to tamper with the lock, or failure to lock the container properly. 
         [0052]    When the container must be opened, the operator uses a coded-signal transmitter to send an access code for unlocking to the coded-signal receiver  38 . The control module  30  operates the bi-stable solenoid  32  to toggle the latch  30  into unblocking position. The operator can now pull the knob  18  to withdraw the head  22  from the recess  24 . Thus the arms  12  and  14  are disengaged. The handles  7  may be rotated inwards to release the rods  5  from the braces  6  and the doors  2  and  3  may be opened. 
         [0053]    The coded-signal receiver  48  and the wireless transmitter  46 , in the general case, are different devices and use different media for communication. For example, the coded-signal receiver may be even a keypad or a touch pad. However, in some applications they may be integrated, for example, in a single RF transmitter-receiver. 
         [0054]    The waveguide may be formed so that other attempts to manipulate elements of the container can be detected. With reference to  FIGS. 2A and 2B , the arms  12  and  14  are joined to the rods  5  by means of semi-circular jaws  72 ,  74  rotating about an intermediate cam  76 . The cam  76  is secured to the rod  5  and has a tooth  78  received in a circular channel  80  of the jaws  72 ,  74 . With reference to  FIG. 3A , the circular channel  78  crosses the wave guide  52  on the arm  14  forming the air gap (recess)  68 . When the arms  12  and  14  are in closed position, the tooth  78  is clear of the recess  68  and the IR pulse can pass through the gap ( FIG. 2B ). If an attempt is made to rotate the rod  5 B inward (i.e. to release it from the braces  6 ), the tooth  78  will enter the recess  68  and will obstruct the waveguide  52 . This relative position is seen in  FIG. 2A . 
         [0055]    Preferably, the lock arms are of strong construction, for example pressed or machined from steel, and the waveguide channel is also machined therein. The channel is preferably disposed close to external edges of the lock arms so that an attempt to break or cut the arms would first interrupt the channel. 
         [0056]    Another embodiment of the present invention is a sealing lock  100  shown in  FIGS. 4A ,  4 B,  5 A and  5 B. Here the bolt is actually a seal  116  comprising a head  122  with a flat breakable portion  123  and a flat tail  118 . The head  122  has a step  124  and a shoulder only at one side. The recess  24  has a narrow notch  120  adapted to receive only the flat breakable portion  123 . A latch  130  is urged to its blocking position by means of a compression spring  132  instead of a bidirectional drive. 
         [0057]    The sealing lock operates in the following way. The seal  116  is inserted into the bore  19  of the arm  14  before aligning with the arm  12 , with the tail  118  forward, until the position of  FIG. 4A  is reached (but without the arm  12 ), with the step  124  and the shoulder of the head  122  abutting the latch  130 . Then, using a key to hold the flat tail  118 , the bolt  116  is rotated to about 90° so that the latch  130  is pushed against the spring  132  and releases the shoulder. The operator pulls the seal  116  further into the bore  19  until the breakable part  123  sinks into the bore. Then the operator aligns the arm  12  with the arm  14  so that the recess  24  is aligned with the bore  19 . The seal  116  is rotated back and pushed up. The flat breakable part  123  is aligned with the notch  120  and received therein. The seal  116  assumes its locking position and the latch  130 , urged by the spring  132 , automatically jumps under the head  122  blocking the seal ( FIG. 4A ). 
         [0058]    The flat part  123  of the seal  116  is now locked in the notch  120  and the seal cannot be rotated. Thus, the position of  FIG. 4A  is irreversible and the seal  116  can by removed from its locking position only after applying force on the tail  118  to break off the flat part  123 . 
         [0059]    The mounting of the arms  12  and  14  on the rods  5  is shown in detail in  FIGS. 6A ,  6 B and  6 C. The intermediate cam  76  comprises two halves  76 A and  76 B coupled by a dovetail joint  82 . One of the halves,  76 B, has threaded bores  84  for set screws  86 . The assembly of the cam  76  on the rod  5  is carried out as follows. The first half  76 A is held in place between the rod  5  and the container wall. The second half  76 B is born on the rod above or below the first half and the dovetail joint is engaged by axially sliding the second half in place. Now the set screws are tightened. 
         [0060]    The rotary joint of the arms  12  and  14  with the cams  76  is assembled in the following way. An arm, for example the arm  12 , is hanged on the rod  5  above or under the cam  76  and is rotated to 180° of its closed position so that the tooth  78  is axially aligned with the gap between the jaws  72  and  74 . The arm  12  is moved along the rod axis until the tooth  78  is aligned with the channel  80 . The arm  12  is now rotated to its closed position. The tooth  78  engages the channel  80  and prevents sliding of the arm along the rod  5 . In order to avoid accidental rotation of the arm to the position where the tooth  78  may fall into the gap between the jaws  72  and  74 , a bolt  88  is screwed into the jaw  72  so that its tip abuts the tooth  78 . 
         [0061]    With reference to  FIG. 7A , there is shown a seal  210  according to another aspect of the present invention. The seal  210  comprises a seal body  212  and a U-shaped shackle  214 . 
         [0062]    The shackle  214  has two ends  216  with taper or bevel  218  and notches  220  at the inner side of the U-shape. Furthermore, the shackle has a central channel (waveguide)  222  extending along the U-shape and exiting at the faces of the ends  216 . 
         [0063]    The body  212  has two cylindrical bores  224  for accommodating the ends  216 , and a transverse cylindrical bore  226  with two bolts  228  sliding therein and biased outwards by a spring  230 . The bolts  228  have notches  232  engaged with stoppers (not shown) protruding inside the bore  226  so as to limit the axial travel of the bolts  228  either way. An electronic control module  40  similar to the one described with reference to  FIG. 3A  comprises an IR emitter  42 , IR receiver  44 , a wireless (e.g. RF) transmitter  46 , a coded-signal receiver  48 , and other electronic circuitry. 
         [0064]    The operation of the seal  210  is as follows. The shackle  214  is first passed through suitable openings in a container cover, a door or any enclosure that has to be sealed. The ends  216  of the shackle  214  are then inserted in the bores  224  of the seal body  212 . With reference to  FIG. 7B , the bevel  218  urges the bolt  228  into the bore  226  so that the shackle can enter the body  212  all the way down the bores  224 . When the notch  220  comes entirely opposite the bolt  228 , the latter jumps into the notch urged by the spring  230  and locks the shackle  214  to the body  212  (this position is shown in  FIGS. 7A and 8A ). 
         [0065]    The locked state of the seal is irreversible, e.g. the seal cannot be opened without being broken, as the spring  230  does not allow bolts  228  to leave the notches  220  and release the shackle  214 . In this state, the exits of the waveguide  222  are aligned with the IR emitter  42  and the IR receiver  44  so that the integrity of the seal may be checked by sending and detecting IR pulses as described above. 
         [0066]    When the locked enclosure has to be legitimately opened, a powerful cutting tool  234  is used to cut or break the shackle  214  into two separate parts. Now each part can be rotated in its cylindrical bore  224 . As shown in  FIG. 8B , by way of rotation to about 90°, the end  216  pushes the bolt  228  back into the bore  226  so that the shackle part may be pulled out of the seal body  212 . For the next sealing, a new shackle  214  is used. 
         [0067]    With reference to  FIG. 9 , a composite shackle  240  is shown which is made of an external steel tube  242  and a rubber or plastic internal tube  244  accommodating the waveguide channel  222 . While the external tube is strong, the internal tube is soft and tends to close the waveguide upon slight deformation which may occur at an attempt to break the shackle. The steel tube may be bent and thermally hardened before the soft tube is inserted. The strength of the shackle can be adapted to the purpose of application by selecting the shackle diameter, steel grade, hardening, etc. 
         [0068]    The seal  210  may be used not only with IR light but may be built with an optical fiber, electric wire or other type of conductor.

Summary:
Locks and seals for containers, in particular those including an automatic self-checking and warning system against tampering, are provided. The lock has an infra-red (IR)-bases mechanism, with an IR emitter and an IR receiver, communicating through a waveguide such that an IR pulse emitted by the IR emitter can pass through the waveguide and be received by the IR receiver only when the lock is in the closed state. The seal has a U-shaped shackle engaged in a seal body irreversibly locking said shackle to the body. Only when the shackle is broken into two separate parts, each part can be rotated to disengage the cylindrical end so that the broken part may be pulled out of the body.