Abstract:
A shutter plate for a self-locking cover for a telephone paystation coin receptacle includes a coupler for joining a shutter control arm to the shutter plate that deforms when a force having a predetermined magnitude is applied to the control arm. The deformation of the coupler provides an indicator that an attempt to move the shutter plate to expose an aperture in the self-locking cover has occurred. The coupler may be one or more holes in a portion of the shutter control arm that is external of the self-locking cover. The coupler may take the form of a weld that joins the shutter control arm and the shutter plate. Frangible material may also be used to fill openings in the control arm to provide a tamper indicator. The tamper indicator facilitates detection of tamper attempts by visual inspection.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to coin operated telephone paystations, and more particularly, to self-locking covers for coin receptacles which collect money inserted into telephone paystations. 
     BACKGROUND OF THE INVENTION 
     Self-locking coin receptacles are used with telephone paystations to facilitate coin collection. Most self-locking coin receptacles of the major telephone paystation manufacturers (e.g., AT&amp;T, Nortel, Lucent, BellSouth, Pacific Bell, U.S. West, Ameritech, Bell Atlantic and GTE) are similar. The basic operation of self-locking coin receptacles is described in detail in U.S. Pat. No. 3,837,566 to McGough, incorporated herein by reference. 
     A self-locking coin receptacle includes a receptacle and a self-locking aperture cover. The self-locking aperture cover has mounted within it a shutter plate and a shutter control arm that extends externally of the cover to engage a bracket in the vault within the paystation. Sliding the receptacle into the vault of a paystation moves the control arm which opens a shutter covering an aperture within the cover. Coins traveling down a coin track pass through the open aperture to the receptacle. When the receptacle is removed from the paystation, a biasing member moves the shutter plate so it closes the aperture to the receptacle. The cover includes a latching mechanism that blocks movement of the shutter plate so the aperture remains closed and easy access to the contents of the receptacle is thereby denied. 
     Self-locking receptacles were developed so the receptacle could be removed from a paystation and transported to a safe collection facility rather than having the employee empty the receptacle at the paystation. Accumulation of money from receptacles at multiple paystations results in sums of money that may entice robbery attempts and present risks to the service personnel. The incentive for robbery declines if a thief has to defeat a locking mechanism to access the contents of each receptacle a service person may possess. Also, the self-locking covers help deter employees from taking a portion of the money contained within the receptacles of paystations on a service route. 
     Attempts have been made to design self-locking coin receptacles that are substantially tamper proof or that indicate whether tampering or tampering efforts have occurred. For example, U.S. Pat. Nos. 4,194,775 to Shea, 5,515,030 to Citron, et al. and 4,204,709 to Shea disclose systems that improve the locking engagement between a self-locking cover and its coin receptacle. However, telephone paystation companies have discovered that some self-locking covers can be forced open and the contents of the receptacle accessed without leaving readily noticeable signs of tampering. Thus, service personnel may be able to remove some or all of the contents of a coin receptacle without providing any indication of receptacle tampering. 
     SUMMARY OF THE INVENTION 
     The limitations of known self-locking covers for coin receptacles are overcome by a self-locking receptacle made in accordance with the principles of the present invention. The present invention provides a system that indicates that an attempt to forcibly open the cover aperture has occurred. The system includes a shutter for selectively blocking an aperture to a self-locking coin receptacle, a shutter control arm coupled to the shutter, and a tamper indicator operatively coupled to the shutter control arm, the tamper indicator responding to a force of a predetermined magnitude to indicate an attempt was made to move the shutter control arm to expose the aperture in the self-locking coin receptacle while the shutter was in a locked position. The tamper indicator facilitates visual inspection of the exterior of a self-locking receptacle to detect a tamper attempt. 
     The predetermined magnitude of the force to which the tamper indicator responds is selected to be less than the force necessary to defeat the latching mechanism that resists movement of the shutter to expose the coin aperture. The tamper indicator may be a coupler that joins the shutter control arm to the shutter. The coupler may be made of a zinc-aluminum alloy. Alternatively, the coupler may be a weld of material that joins the shutter control arm and shutter and that deforms in response to a force a little less than the predetermined magnitude. In another to embodiment the coupler includes at least one opening defined in the shutter control arm that causes the coupling to deform in response to a force a little less than the predetermined magnitude. The opening may be filled with a frangible material that shatters when a force at the predetermined threshold is applied to the control arm. For example, the material may be a ceramic material or a polymer material. 
     Another embodiment of the invention provides a self-locking coin receptacle cover for use with a coin receptacle. The cover includes a cover base having an aperture, a shutter plate rotatably mounted to the base, the shutter plate having a shutter control arm, a portion of which is external of the cover base to move a portion of the shutter plate so it selectively blocks the aperture, a latching mechanism for blocking movement of the shutter plate, and a tamper indicator operatively coupled to the shutter control arm, the tamper indicator responding to a force applied to the shutter control arm to indicate an attempt was made to move the shutter control arm to uncover the aperture when the shutter was in a locked position. 
     The shutter control arm is preferably deformed when a force is applied to the shutter control arm in a direction that opens the aperture and the force approaches the force necessary to cause the shutter plate and a prong in the latching mechanism to slip by one another. 
     Accordingly, an object of the present invention is to provide a self-locking coin receptacle cover that cannot be forced open without leaving irreversible signs of tampering. One advantage of the present invention is that it works with the current installed base of paystations and another is that it is cost-efficient to manufacture. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a known self-locking cover and coin receptacle; 
     FIG. 2 is a plan view of the outer wall of the coin receptacle cover of FIG. 1; 
     FIG. 3 is a plan view of the underside of the outer wall shown in FIG. 2; 
     FIG. 4 is a plan view of an embodiment of a shutter configured with an opening in the shutter control arm to weaken the arm; 
     FIG. 5 is a plan view of an embodiment of a shutter plate configured with a control arm having an L-shaped flange at its outboard end; 
     FIG. 6 is a plan view of an embodiment of a shutter plate made from zinc-aluminum alloy; 
     FIG. 7 is a plan view of an embodiment of a shutter plate having a control arm joined to the plate by a weld; and 
     FIG. 8 shows the shutter plate of FIG. 3 with the opening being filled with a frangible material. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A description of the preferred embodiment of the present invention is provided in connection with the accompanying figures. Like reference numerals are used in the figures to identify the same structural elements, portions or surfaces throughout the several drawings figures, as such elements, portions or surfaces may be further described or explained by the entire written specification, of which this detailed description is an integral part. The drawings are intended to be read together with the specification, and are to be considered a portion of the entire written description of this invention. 
     FIG. 1 shows a self-locking coin receptacle  10  comprising a cover  12  and a coin receptacle  14 . Cover  12  includes a base  16  having an aperture  18  defined therein and a shutter  20 . Shutter  20  is a portion of shutter plate  42  (FIG.  3 ). Shutter plate  42  is rotatably mounted about a pin so shutter plate  42  moves in a plane between inner wall  16   a  and outer wall  16   b  of base  16 . Shutter plate  42  also includes a control arm  22  that extends through slot  24  and bends at approximately a 90° angle so it is approximately parallel to outer wall  16   b  extends beyond edge  30  of cover  12 . Movement of control arm  22  in arcurate slot  24  moves shutter  20  to open or close aperture  18 . Cover  12  is coupled to receptacle  14  by hinge elements, such as offset hinge arms extending from outer wall  16   b  of cover  12  that are received within slots formed or cut within lip  32  of receptacle  14 . Such hinges are merely exemplary and are not shown in the figures as they are well known. Other hinge constructions may be used. A closure member  36  extends from cover  12  and its outboard end may include an extension that is functionally snapped into receiving indentation  38  or the outbound end may include a slot that receives a locking tab mounted on receptacle  14 . Again, such structure in coin receptacles is known in telephone paystations. Mounted between inner wall  16   a  and outer wall  16   b  is a latching mechanism  34  (FIG. 3) that includes a reset arm  26  that extends through elongated opening  28 . Latching mechanism  34  engages shutter plate  42  to control its freedom of movement about its mounting pin. Moving reset arm  26  to its first position (FIG. 2) causes shutter  20  to be biased into a position that blocks aperture  18 . 
     FIG. 2 shows outer wall  16   b  of cover  12 . In the figure, aperture  18  is closed by shutter  20  and shutter control arm  22  extends beyond the periphery of cover  12 . At position A, coin receptacle  14  is locked and ready for insertion in the vault of a telephone paystation. As receptacle  14  is slid along the rails of the bracket within the vault of a paystation, control arm  22  is engaged by the bracket so it moves along slot  24  to position B and thereby rotates shutter  22  to open aperture  18 . Latching mechanism  34  is also engaged by shutter plate  42  so control arm  22  is biased to rotate shutter  20  and close aperture  18  as receptacle  14  is removed from the vault of a paystation. Upon return to position A, latching mechanism  34  blocks movement of control arm  22  within slot  24  so aperture  18  remains closed by shutter  20 . 
     Self-locking coin receptacle  10  is prepared for deployment at a paystation by moving reset arm  26  to unlock shutter  20  so it returns to its biased position which closes aperture  18 . Cover  12  is pivoted about its hinge to close coin receptacle  14  and closure member  36  is secured to receptacle  14  as is well known in the art. A service person then takes a group of locked coin receptacles  10  to swap with those deployed at paystations. After removal of a coin receptacle from a paystation, coin receptacle  10  is inserted into the vault of a paystation by sliding the receptacle between the rails of a bracket (not shown) within the vault. When the self-locking coin receptacle  10  is inserted into the vault, shutter control arm  22  engages the edge of a slot in the bracket which causes the unlocked shutter  20  to open as the shutter control arm  22  moves along arcurate track opening  28 . Insertion of coin receptacle  10  and the movement of shutter plate  42  triggers latching mechanism  34  to cooperate with shutter plate  42  and control shutter  20 . 
     FIG. 3 shows the underside of outer wall  16   b  of cover  12 . Shutter plate  42  is shown in the position where shutter  20  closes aperture  18 . Prong  36  of latching mechanism  34  and shutter plate  22  rest above plate  38 . Prong  36  abuts and blocks shutter plate  42  as control arm  22  moves from position A in slot  24 . This action of prong  36  prevents aperture  18  from being uncovered by shutter  20 . Prong  36  and shutter plate  42  are moved to the locked position shown in FIG. 3 when a self-locking coin receptacle is removed from a telephone paystation vault. 
     In previously known shutter locking devices, sufficient force applied to shutter control arm  22  can cause shutter plate  42  and prong  36  to deflect in opposite directions when prong  36  is locked by latching mechanism  34  so shutter plate  42  can move over or under prong  36 . This movement permits shutter  20  to uncover aperture  18  and provide access to coin receptacle  14 . After coins are removed from the coin receptacle, force may then be applied to control arm  22  to substantially reverse the deflection of the shutter  20  and prong  36  and return shutter  20  to its closed position. Cover  12  then appears to be in its original locked position and evidence of tampering is not readily apparent. A person who performed the theft can turn in the self-locking coin receptacle with little fear of detection. Even if the tampering is noticed after a thorough inspection, the inspector cannot ascertain whether the tampering occurred on the current service run or a prior service run. 
     The present invention deters theft by making readily identifiable an attempt at tampering with shutter control arm  22  once latching mechanism  34  is engaged. The present invention helps make tampering readily apparent by providing a connection or coupling between shutter control arm  22  and shutter  20  that breaks or decouples or that deforms in response to a force being applied to shutter  22  when prong  36  is locked by latching mechanism  34 . That is, the force necessary to break the coupling or connection or to deform the shutter control arm is less than the force required to deflect prong and shutter so they pass over one another. The decoupling, breaking or deformation may be more easily detected than evidence of tampering occurring on previously known coin receptacles. 
     FIGS. 4-7 show various embodiments of a shutter plate that are constructed according to the principles of the present invention. Shutter plate  50  of FIG. 4 includes a body  52  and a shutter control arm  54  having an opening  56  defined therein that weakens shutter control arm  54 . This weakened portion causes shutter control arm  54  and opening  56  to deform or causes one or both of the arms surrounding opening  56  to break in response to a force being applied to shutter control arm  54  that would deflect shutter plate  50  to pass prong  36 . Such deformation or breakage readily identifies coin receptacle tampering without requiring cover  12  to be removed from coin receptacle  14 . 
     Shutter control arm  54  should be strong enough to engage and work with the bracket of the paystation vault as intended without deformation or failure in normal operation. Thus, any deformation or failure of shutter control arm  54  cannot be blamed on normal wear and tear. The shutter plate and shutter control arm of the present invention may be used in previously known designs for self-locking coin receptacles by simply replacing the previously known shutter plates with the shutter plate of the present invention. Accordingly, the invention is compatible with the majority of the installed base of telephone paystations and can be produced at a cost similar to previously known self-locking coin receptacles. 
     Shutter plate  60  of FIG. 5 is another embodiment of a shutter constructed in accordance with the principles of the present invention. Shutter plate  60  includes a generally L-shaped flange  66  that terminates shutter control arm  62  and weakens the structural integrity of the control arm  62 . The L-shaped shutter control arm  62  may have an opening defined therein to further weaken the arm as discussed above. The length and width of L-shaped flange  66  closely corresponds to the length and width of control arm  22  that extends from slot  24 . This is preferably done to render shutter plate  60  compatible with known coin receptacles although the dimensions of shutter arm  62  may be adopted for other designs without departing from the principles of the present invention. 
     FIG. 6 shows shutter plate  80  which has the same general shape as shutter plate  42  discussed above. Whereas shutter  20  is traditionally made of a steel alloy, shutter  80  is made of a material more malleable or brittle than steel alloys. Specifically, shutter plate  80  and/or shutter control arm  82  is preferably made of a zinc-aluminum alloy. The thickness of connecting arm  86  that couples shutter control arm  82  to shutter plate body  84  is selected so that a force applied to shutter control arm  82  that forces the shutter plate past the prong in known covers causes shutter control arm  82  to permanently deform or break from body  84 . 
     Referring to FIG. 7, shutter plate  90  is generally the same shape as shutter plate  42  but instead is constructed in two pieces rather than an integral structure. Shutter control arm  92  and body  94  are welded together at welding junction  96 . Weld  96  fails (e.g., deforms by breaking or bending) upon the application of a force to shutter control arm  92  that is less than the force required to pass shutter  90  by a latching mechanism prong  36  when shutter plate  90  and the prong are in the locked position. While a weld is the preferred coupling structure of this embodiment other joining materials, such as adhesives or other chemical bonds, may be used in like manner. 
     Referring to FIG. 8, another embodiment of the present invention is illustrated. The embodiment illustrated in FIG. 8 has the same basic shutter design and shutter control arm design as the embodiment discussed in connection with FIG. 3; however, opening  56  provides an additional indication that an attempt has been made to open the shutter of a self-locking coin receptacle when the shutter is in its closed or locked position. Preferably, opening  56  is filled with a frangible material that shatters, breaks, or otherwise is permanently altered in response to an attempt to defeat the locking mechanism of a self-locking cover for a coin receptacle box. The material should be made of material that is difficult to replace without an indication of tampering. Such materials may include polymers, ceramic, or other materials such as glass, acrylics, plastic, cement, clay or the like. The material used to fill opening  56  should be sufficiently thick or durable to withstand normal movement of the coin receptacle box without shattering, deforming, or otherwise indicating that a tamper event has occurred. 
     Although preferred embodiments of the invention have been disclosed and described, those skilled in the art will recognize modifications can be made without departing from the scope of the invention. It should be appreciated that the various characteristics the embodiments discussed herein can be combined in accord with the present invention. For example, the shutter control arm can be made of a zinc-aluminum alloy with body made of a steel alloy. As a further alternative, the shutter control arm and body of a shutter may be made of the same material, but of different thicknesses.