Abstract:
An anti-theft device comprising a container formed by a box ( 10 ) and a lid ( 11 ) hinged together. A lock slide ( 15 ) inside the box can be displaced between a disengaged position and an engaged position. A flange ( 22 ) on the lid forms an L-shaped slot. A first limb ( 23 A) of the slot is perpendicular to a free edge of the flange and opens in the edge to receive a projection on the lock slide in the disengaged position thereof. A second limb ( 23 B) of the slot extends transversely of the first limb to receive the projection when the lock slide is in the engaged position. A latch mechanism ( 26, 28 ) latching the lock slide in the engaged position can be actuated by a special tool to unlatch the lock slide and allow displacement thereof to the disengaged position.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to an anti-theft device for displaying particularly expensive and attractive goods in shops and department stores, of the kind comprising a container formed by a first part and a second part hinged together, a lock slide inside said first part, which includes at least one projection and can be displaced manually between an engaged position in which the projection engages said second part to lock the parts together in a closed position of the container, and a disengaged position allowing opening of the container, a latch mechanism for latching the lock slide in the engaged position, which can be actuated by means of a special tool to unlatch the lock slide and allow displacement thereof to the disengaged position, and an element for wireless activation of an alarm if the anti-theft device is carried through an exit of the shop or the department store. 
   2. Description of the Prior Art 
   An anti-theft device of this kind is disclosed in EP 0 616 103 B1 wherein the container comprises a lower-part and a lid, projections on the lock slide and the lid inter-engaging in the closed position of the container. The lock slide is mounted in the lower-part for displacement along a partition therein. In the engaged position the lock slide is latched to the partition by means of spring blades on the partition which engage the lock slide and can be disengaged by the spring blades being actuated mechanically or magnetically in order to allow displacement of the lock slide to the disengaged position when the container is to be opened. 
   This prior art anti-theft device does not provide a satisfactory protection against theft of the objects displayed in the container because it can be opened too easily by means of a tool inserted between the lower-part and the lid the projections being broken off when the lower-part and the lid are separated by means of the tool. 
   EP 0 731 870 B1 describes an anti-theft device wherein the lock slide is provided with lock bolts which are brought into and out of engagement with the box by means of the lock slide which is operated by means of an operating slide parallel with the lock slide. The operating slide can be displaced back and forth manually and is operatively connected with the lock slide in such a way that the displacement of the operating slide is converted into a displacement of the lock slide in the transverse direction of the displacement of the operating slide. The lock slide is latched in the locking position by means of a latch mechanism described in EP 0581 811 B1. The housing thereof is available on the outside of the anti-theft device and forms a finger grip for the manual displacement of the operating slide between engaged and disengaged position. 
   The anti-theft device disclosed in EP 0 731 870 B1 is of a complicated construction as the lock mechanism thereof includes two slides, a lock slide and an operating slide, operatively interconnected. 
   BRIEF SUMMARY OF THE INVENTION 
   The object of the invention is to overcome the drawbacks of the prior art anti-theft devices described above. 
   For this purpose the invention provides an anti-theft device of the kind referred to herein which according to claim  1  is characterized in that a flange on said second part-forms at least one L-shaped slot a first limb thereof opening in a free edge of the flange to receive the projection therein at closing of the container with the lock slide in the disengaged position, and a second limb extending transversely of said first limb and receiving the projection when the lock slide is displaced to the engaged position. 
   Further features of the invention are defined in the dependent claims. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     Illustrative embodiments of the anti-theft device will be described with reference to the accompanying drawings in which 
       FIG. 1  is a top plan view of a first embodiment of the device, 
       FIG. 2  is a side view of the device in  FIG. 1 , 
       FIG. 3  is a cross sectional view along line III—III in  FIG. 1 , 
       FIG. 4  is a cross sectional view along line IV—IV in  FIG. 2 , 
       FIG. 5  is a cross sectional view along line V—V in  FIG. 2 , 
       FIG. 6  is an enlarged plan view of a plate forming a spring tongue, 
       FIG. 7  is a central longitudinal cross-sectional view of the plate in  FIG. 6 . 
       FIG. 8  is a fragmentary side view of the lower portion of one of the parts forming the container, as seen from the inside of said part, 
       FIG. 9  is a view, corresponding to  FIG. 8  of the other part of the container, 
       FIG. 10  is a view, corresponding to  FIGS. 8 and 9  with the two parts of the container hingedly interconnected and shown in an open position, 
       FIG. 11  is a fragmentary side view of the lower portion of the closed container, as seen from the outside thereof, a hanger to be attached to the container being shown in side view, separated from the container, 
       FIG. 12  is a view as that in  FIG. 11  with the hook attached to the container, 
       FIG. 13  is a fragmentary transverse cross sectional view of the lower part of the container showing the attachment of the hanger, 
       FIG. 14  is a fragmentary cross sectional view as that in  FIG. 3  of the top portion of a second embodiment of the device shown in the locked position, and 
       FIG. 15  is a view corresponding to that in  FIG. 14  of the device in the unlocked position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The anti-theft device shown in  FIGS. 1 to 14  of the drawing comprises a parallelepipedic container for receiving the object or objects to be protected against theft, which is formed by a box  10  and a lid  11 . The box has an upper end wall  12  with a flat outside surface  13  and a flat inside surface  14  the surfaces being parallel with each other. Lid  11  is connected with the box by a hinge to be described in more detail below, for swinging movement as indicated by a double arrow in  FIG. 4 , between open and closed position. The lid forms a side wall of the container in the closed position thereof. The box and the lid preferably are injection molded of suitable rigid and strong plastics preferably transparent plastics. 
   A lock mechanism for locking the lid in the closed position includes a flat lock slide  15  which can be displaced longitudinally along surface  14  between a left end position and a right end position. Such displacement is effected manually by means of an outside finger-grip  16  which is located on surface  13  and is connected with the lock slide  15  by means of a pin  17  extending through end wall  12  the pin being displaceably received in a longitudinal slot  18  in end wall. 
   Lock slide  15  forms a unit together with a flat rail  19  which extends along the lock slide and is connected therewith by three pins  20  mutually spaced, a space  21  being provided between the lock slide and the rail. 
   Lid  11  forms a flange  22  projecting at right angles from the inside surface of the lid at the upper end thereof. The flange is dimensioned to be received in space  21  provided between lock slide  15  and rail  19 , and forms three L-shaped slots,  FIG. 5 , having a limb  23 A at right angle to the free edge of the flange and opening at said edge, and a limb  23 B at right angle to limb  23 A and extending longitudinally of the flange. Limbs  23 A are mutually spaced and the spacing thereof is the same as the spacing of pins  20 . 
   With the lock slide and thus the rail in the left end position pins  20  are in register with limbs  23 A, and when the lid is being closed and the flange is being received in space  21 , pins  20  will be received in limbs  23 A. By displacement of the lock slide to the right end position the pins will be displaced along limbs  23 B to the position shown in  FIG. 5 . With pins  20  in this position flange  22  is caught between the lock slide and the rail with the container closed, in order to release the lid the lock slide with the rail has to be displaced to the left end position so that the pins are located in register with limbs  23 A and flange  22  can be withdrawn from the space between the lock slide and the rail at opening of the container. 
   In order to securely lock lid  14  in the closed position the device comprises a latch mechanism for latching the lock slide in the right end position. The latch mechanism is of the type disclosed in WO-A-00/75469 and comprises two U-shaped shallow depressions  24  in surface  14  said depressions being mutually spaced in the longitudinal direction of end wall  12 . A plate  25  of spring steel has a centrally punched tongue  26  which is directed obliquely downwards from the plate, the plate being U-shaped with a web from which the tongue extends, and two limbs one at each side of the tongue. The shape of plate  25  is in agreement with the shape of depression  24 , and in each of these depressions such a plate is loosely placed with tongue  26  directed from surface  14  towards the lock slide  15 . Tongue  26  of each of the plates has the free end thereof in a recess  27  in the upper surface of the lock slide. When the lock slide is in the right end position the tongue engages at the free end thereof a shoulder  28  formed by the recess. The tongues as a consequence thereof prevent displacement of the slide to the left as seen in  FIG. 3  to the disengaged position. Plates  25  shall be of a spring steel which can be attracted by magnets—permanent magnets or electromagnets—being moved externally towards the outside surface  13  of end wall  12  in register with tongues  26 . When the tongues are attracted by the magnets they will be bent upwards against the bottom of the associated depression  24  so that the tongue will be disengaged from shoulder  28  and lock slide  15  will be free for manual displacement to the left end position allowing opening of the lid. 
   The hinge connection between the box  10  and the lid  11  will be described in more detail with reference to  FIGS. 2 and 8  to  10 . One of said two parts forming the container of the anti-theft device of the invention—in the embodiment shown lid  11 —forms four mutually spaced sockets  29 , and the other part—box  10 —forms three mutually spaced sockets  30 . The sockets are located such that sockets  30  are received in the spaces between sockets  29 . The sockets are aligned, and a pin  31  is passed through the sockets and is locked in this position by a perpendicularly angled end portion  32  which by rotation of the pin has been located inside the lid abutting an edge wall thereof as shown in  FIG. 10 . Box and lid can easily be separated at the hinge for example in order to replace a box having a certain depth by a box having another depth, smaller or larger, in order to adapt the volume of the container to the size of the goods to be displayed therein. 
   Sometimes it may be desired to expose goods enclosed in anti-theft devices as described in a rack in which each anti-theft device is suspended from a projecting prong. In order to allow suspension of the anti-theft device it can be combined with a hanger  33  formed as a hook or an eye,  FIGS. 11 to 13 , which forms two forked projections  34 . This hanger is attached to exposed portions of pin  31  at the forked projections. Preferably this is done with the lid open, and then, when the lid is closed, the forked projections will be clamped between the box and the lid providing a secure connection of the hanger to the anti-theft device. 
   In a modification of the embodiment described above rail  19  is dispensed with, which does not make the device less effective. However, it is preferred that the anti-theft device is provided with such a rail because the lock mechanism is more sturdy if flange  22  in the closed condition of the container is received in space  21  between lock slide  15  and rail  19 . 
   In the embodiment disclosed in  FIGS. 14 and 15  the box and the lid are interconnected by a hinge e.g. of the type described above. The lock slide  15 ′ is made integral with a housing  35  which is mounted in an opening  36  in end wall  12  for displacement of the lock slide along the flat inside surface  14  of wall  12 . The housing forms a finger grip for manual displacement of the slide and is open at the bottom thereof. The mounting of the slide can be made as described in EP 0 731 870 B1. Pins  20  on the slide co-operate with L-shaped slots  23  in flange  22  projecting from lid  11  as described above. However, the latch mechanism for latching the lock slide in the engaged position differs from that provided in the embodiment first described. The latch mechanism principally is of the type described in EP 0581 811 B1 and comprises a spring tongue  37  mounted in the housing at one end  38  thereof. The spring tongue is made of a material which can be attracted by a magnet and forms an angled flap  39  at the other end thereof. When the lock slide is in the engaged position the spring tongue engages at flap  39  an aperture  40  in flange  22  as shown in  FIG. 15 . The spring blade can be disengaged from flange  22  by means of a magnet which attracts the spring tongue so that flap  39  is withdrawn from aperture  40  and the lock slide can be displaced for moving pins  20  from limbs  23 B of the L-shaped slots in flange  22  so that the pins are located in register with limbs  23 A and the lid can be opened, all in the same manner as described with reference to the first embodiment. 
   The anti-theft device should be provided with an element (not shown herein) for wireless actuation of an electronic alarm if the device is carried through an exit of a shop or department store or a defined area therein, as is well known in the art.