Patent Publication Number: US-6701854-B1

Title: Detonator to be installed in a chamber and safety container comprising it

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a detonator intended to be installed in a chamber equipped with a blockable access opening, of the type comprising a member for initiating a pyrotechnic chain. 
     The invention also relates to a security container of the type comprising a chamber equipped with a blockable access opening and, placed in the said chamber, a pyrotechnic charge associated, within a pyrotechnic chain, with a triggering detonator also placed in the said chamber. 
     A security container of this type is described, for example, in document EP-A-0,188,155. 
     In this document, the container is intended for the transportation of valuables, especially banknotes. 
     The pyrotechnic charge is formed by a detonating cutting cord which is initiated by a detonator. The cutting cord and the charge are both placed inside the lid of the container. 
     The presence of detonating pyrotechnic means is a source of substantial risk to the user of the container. 
     In particular, when access to the container is open, accidental triggering of the detonator causes the firing of the pyrotechnic charge and may thus cause serious injury to anybody in the vicinity of the open container. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide a solution to this safety problem preventing the risk of injury to those responsible for handling the valuables contained in security containers equipped with pyrotechnic means. 
     To this end, the subject of the invention is a detonator intended to be installed in a chamber equipped with a blockable access opening, of the aforementioned type, characterized in that it comprises a casing for confining the said initiation member, which casing comprises, facing the said initiation member, a port for igniting a pyrotechnic charge placed in the said chamber outside the said casing, in that it comprises a shutter for blocking the said port which can be moved between a retracted position clear of the said port and a position for blocking this port, and in that it comprises means of operating the said shutter which are designed to keep it in its retracted position when access to the said chamber is blocked, and keep it in its blocking position when access to the said chamber is open. 
     According to particular embodiments, the detonator may have one or more of the following features: 
     it comprises a spring urging the said shutter into its position of blocking the said port, and the said operating means comprise a push-rod designed to move the said shutter clear when blocking the said access; 
     the said push-rod at least partially bears the pyrotechnic charge, and a part of the pyrotechnic charge can be moved with respect to the casing to take the place of the blocking shutter facing the said port; 
     it comprises a pyrotechnic initiation relay between the said port and the said initiation member; and 
     the said operating means comprise an actuator, particularly an electromagnet, for moving the said shutter, which actuator is connected to a control unit comprising means of detecting whether or not the said access to the chamber is open. 
     Another subject of the invention is a security container of the aforementioned type, characterized in that the said detonator is a detonator as defined earlier. 
     According to one of the particular embodiments, the container has one or more of the following features: 
     it comprises means of locking the access and the member for initiating the pyrotechnic chain is connected to an electric control circuit via a switch that selectively connects the said initiation member to the said electric control circuit, and it comprises mechanical means of operating the said switch in order to connect the said pyrotechnic initiation member when the said access is locked and disconnect the said pyrotechnic initiation member when the said access is unlocked; 
     it comprises two articulated half-shells forming a suitcase and a detonator housed in the said suitcase, and the said casing for the detonator is fixed to a first half-shell, the push-rod being fixed to the second half-shell facing the said casing; and 
     the access opening comprises a door and the said chamber forms a strongbox, the said detection means comprising sensors that sense whether or not the said door is open. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood from reading the description which will follow, given merely by way of example and made with reference to the drawings in which: 
     FIG. 1 is a view in perspective of an open security suitcase according to the invention; 
     FIGS. 2 and 3 are views in perspective on a larger scale, of the two parts of the detonator of the suitcase of FIG. 1; and 
     FIG. 4 is a partially diagrammatic view in perspective of a detonator according to the invention, intended for a strongbox. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The suitcase  10  depicted in FIG. 1 comprises two half-shells  12  and  14  articulated together. 
     This suitcase forms a security container delimiting a chamber  16  for holding valuables to be transported, such as banknotes, computer data media or electronic components. 
     The chamber  16  is equipped with an opening in its upper part. This access opening can be blocked by the upper half-shell  14  which forms a lid. 
     A pyrotechnic charge  18  formed by a detonating cutting cord is fixed along the entire length of the interior face of the lid  14 . This pyrotechnic charge is designed to destroy the valuables contained in the container, at least partially, in the event of any attempt to tamper with this container. This pyrotechnic charge is advantageously associated with means for throwing ink over the valuables contained in the suitcase. These throwing means are formed, for example, by ink reservoirs with frangible walls. 
     The cord  18  is connected to a detonator  20  designed to trigger the pyrotechnic charge. This detonator comprises a first part denoted  22 , fixed to the lower half-shell  12  of the suitcase, and a second part denoted  24 , fixed to the lid  14  facing the first part  22 . 
     These first and second parts are depicted in FIGS. 2 and 3 respectively. 
     The first part  22  is electrically connected to a control unit, not depicted, itself connected to sensors that detect an attempt to break into the suitcase. These sensors are, for example, sensors that sense opening or alternatively, displacement sensors. 
     As depicted in FIG. 2, the first part  22  of the detonator comprises a confinement casing  26  in which an electrically controllable member  28  for initiating the pyrotechnic chain is placed. 
     The casing  26  is produced by the assembly of two symmetrical half-shells denoted  26 A,  26 B, formed from machined solid metal blocks. From the outside, this casing is approximately in the shape of a rectangular parallelepiped. 
     It comprises a cut-out  30  formed at the centre of a corner, secant to the longitudinal mid-plane along which the two half-shells  26 A,  26 B are joined. A port  32  is formed facing the said initiation member  28 . It opens out into a face  30 A of the cut-out  30 . 
     Advantageously, the initiation member  28  has an approximately cylindrical shape and is placed in a cylindrical duct  34  extended by the port  32 . 
     The other end of the duct  34  is, extended by an opening  35  intended for the passage of the wires from the control unit. 
     A shutter  36  formed by a metallic cube is mounted so that it can be moved by sliding in a blind duct  38  of square section extending at right angles to the axis of the initiation member  28 . The duct  38  opens out only onto the second main face, denoted  30 B, of the cut-out. The ducts  34  and  38  extend at right angles to one another. 
     In the direction at right angles to the axis of the ducts  34  and  38 , the shutter  36  has a length that slightly exceeds the width of the cut-out  30 . In addition, the duct  38  is interrupted a distance D away from the upper face of the detonator, which means that the shutter  36  is held captive inside the duct  38 . 
     The shutter  36  can be moved from a position of blocking the port  32  (the position depicted in FIG. 2) as far as a position retracted into the blind part of the duct  38 , in which position the opening  32  is clear. In the blocking position, the shutter  36  is in contact with the face  30 A of the cut-out. 
     A coil spring  40  is placed in the duct  38 . It is kept loaded between the closed end of the blind duct and the shutter  36  and urges the latter into its blocking position. 
     The second part  24  of the detonator forms a push-rod intended to actuate the shutter  36  and more specifically to retract the latter into the duct  38 . 
     The push-rod  24  comprises a bracket  42  for attaching to a side wall of the lid  14  of the suitcase. Fixed to the end of this bracket is a V section  44  intended to support part of the pyrotechnic charge  18 . 
     For this, a tube  46  with an inside diameter slightly exceeding the outside diameter of the cord  18  is welded into the corner delimited by the section  44 . 
     The cord  18  passes right through the tube  46  and one end, denoted  48 , of the cord  18  protrudes from one of the, ends of the tube  46 . 
     As depicted in FIG. 1, the push-rod  24  is fixed to the interior face of a side wall of the lid  14 , while the body  22  ,of the detonator is fixed facing the push-rod on the interior face of the corresponding wall of the lower half-shell  12  of the suitcase. 
     When the suitcase is open, as, depicted in FIG. 1, the shutter  36 , urged by the spring  40 , is kept in the position of blocking the port  32 . Thus, any accidental triggering of the initiation member has no consequence detrimental to anybody in the vicinity of the suitcase, because the explosion is then confined inside the casing  26 . 
     However, when the lid  14  of the suitcase is closed, the push-rod  24 , and in particular the lower face of the section  44  pushes the blocking shutter  36  into the blind part of the duct  38 . 
     Thus, the end  48  of the cutting cord takes the place of the shutter  36  immediately facing the port  32 . The end  48  is then aligned with the initiation member  28 . 
     If one of the sensors detects an attempt at breaking into the suitcase, the triggering of the initiation member  28  causes the firing of the cutting cord  18  which then destroys the valuables contained within the suitcase. 
     In order further to improve safety when opening the suitcase, the latter comprises means of opening the circuit that powers the member for initiating the pyrotechnic chain when the suitcase is unlocked. 
     In particular, the suitcase comprises, for locking it, a motorized catch connected to a control device for operating the locking and unlocking of the suitcase. In order to prevent the powering of the pyrotechnic initiation member when the suitcase is unlocked, the keeper of the motorized catch is associated with a push-button placed in the power supply circuit of the initiation member. When the keeper is in the locked position, it depresses the push-button so that the initiation member can be supplied with power. When the keeper of the motorized catch is in the position for unlocking the suitcase, the push-button is released, which means that the initiation member power-supply circuit is open. 
     It will thus be understood that when the suitcase is unlocked, the initiation member cannot be powered which means that it is impossible for the pyrotechnic chain to be fired. 
     FIG. 4 depicts, in perspective, a detonator according to the invention designed to be employed in a strongbox fitted with a door. 
     In this embodiment, the detonator is formed as before from two solid machined half-shells joined together. The confinement casing  50  thus formed comprises a port  52  aligned with an initiation member  54  housed inside the confinement casing. 
     A pyrotechnic initiation relay  56  is placed between the initiation member  54  and the port  52 . 
     A shutter  58 , similar to the shutter  36 , is formed by a metal bar that can be moved in translation between a position of blocking the port  52  (which position is depicted in FIG. 4) and a retracted position clear of this port. The bar  58  is operated by an actuator  60  formed by an electromagnet. 
     The actuator  60  is controlled by a control unit  62 , itself connected to sensors  64  that detect whether the door of the strongbox is open. 
     Furthermore, the interior of the strongbox is fitted, as before, with a detonating cutting cord denoted  66 , just part of which has been depicted in the figure. 
     This cord, like the casing of the detonator, is fixed into the chamber delimited by the strongbox. This chamber is denoted  68 . 
     One end, denoted  70 , of this cord is placed facing the port  52 . Enough space is left between the port  52  and the end of the cord to allow the bar  58  to pass. 
     In this embodiment, the control unit  62  is programmed to control the shutter  58  in order, on the one hand, to keep it in its retracted position when access defined by the door to the chamber is blocked, and on the other hand to keep the shutter in its blocking position when access to the chamber is authorized. 
     As before, it will be understood that when the door to the box is open, the shutter  58  confines the initiation member  54  and the pyrotechnic initiation relay  56  within the casing  50  so that any accidental triggering is without danger. 
     However, when the door to the box is closed, the shutter  58  is moved clear so that the continuity of the pyrotechnic chain is once more ensured. Thus, activation of the initiation member  54  causes the firing of the pyrotechnic initiation relay  56  which in turn triggers the cutting cord  66 . 
     The pyrotechnic initiation relay  56  transfers the flame from inside the casing as far as the end  70  of the cord. In particular, it allows the flame to pass across the space formed for the passage of the shutter  58 . 
     A detonator as described here can be installed in any chamber equipped with an opening. In particular, it can be installed in a building or a work room. In such cases, access is blocked by a door. The initiation member is then confined on the basis of whether or not the door is open, in order to prevent the pyrotechnic chain from being triggered when the door is open. 
     Likewise, a detonator of this kind may be installed in a security cabinet in which a collection of keys or electronic cards is stored.