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CROSS-REFERENCE TO RELATED APPLICATION 
     None. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates generally to locking devices used to lock doors on trucks, buildings, storage containers, railroad cars, freight containers, warehouses and the like, and in particular to a defensively enclosed locking device that resists intruders&#39; attempts to physically overpower the device. 
     2. Description of Related Art 
     Virtually all commercial entities and private citizens have ownership or responsibility for property that must be secured at some time during transportation or storage. The most popular means of securing a storage space containing property is by locking the access to the storage space with a door lock, deadbolt, or padlock. Padlocks are small, very strong, inexpensive, and convenient to use. They provide greater protection than other forms of locks used in storage spaces that are not considered vaults. The simple design, interchangeability, and worldwide availability of these devices add to their usefulness. Therefore, millions of access doors are fitted to receive padlocks. 
     As the value of the stored property increases, so does the incentive for thieves to break into the storage space and steal the property. Property owners most often respond by increasing the size of the padlock, or by using multiple padlocks. Unfortunately, professional thieves can destroy padlocks in a matter of seconds, by employing large steel prybars to leverage and rupture either the locks or the latching assemblies. Thus, secured storage of high value property in a storage space continues to be a problem. 
     Since the loss of high value property is, by definition, economically more devastating than the loss of low value property, enhanced locking and security systems are economically justifiable. To address the problems of secured storage of high value property in a storage space, attempts have been made to design protective coverings for the locks and for latching assemblies. One such attempt is disclosed in U.S. Pat. No. 4,911,486, issued to Anderson. In the &#39;486 patent, a tamper-resistant slide bolt and padlock combination is disclosed. However, in the disclosed design, the latching assembly and lock remain substantially exposed to destruction by forcible entry. Other attempts to provide enhanced security to latch assemblies and locks similarly fail to prevent theft. Many of the assemblies permit visibility of their structure, which allows criminals an opportunity and incentive to further investigate and attempt alternative means for destroying the locks and assemblies. Bolt-cutters are only one of the tools used by thieves. For example, many devices permit sufficient access to the latch bolt to allow the use of a hacksaw. Other devices permit access to the latching assembly with chisels and sledgehammers, long steel prybars, and small explosives. Thus there is a need for a device that provides a secure enclosure for latching assemblies and locks which conceals its structure and is impervious to forcible entry. 
     BRIEF SUMMARY OF THE INVENTION 
     A primary advantage of the present invention is that it provides both a concealed and enclosed lock device. Another advantage of the present invention is that it incorporates the use of reliable and inexpensive padlocks as the locking mechanism. Another advantage of the present invention is that it provides an enclosure that prevents access to the shackle of the padlock. Another advantage of the present invention is that it provides an enclosure that prevents access to the latch. Another advantage of the present invention is that it provides an enclosure that prevents access to the strike plate. Another advantage of the present invention is that it provides an enclosure that resists damage from impact. Another advantage of the present invention is that it provides an enclosure that provides the option of a dual latch mechanism. Other advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed. 
     In a preferred embodiment of the present invention, a concealed and enclosed lock device is disclosed, having a latch box enclosure. The latch box has a backplate, and a baseplate extending outward from the backplate. The backplate has a lock slot. A guide bar having a channel is attached to the backplate. A link is pivotally attached to the backplate on one end, and has an orifice on the opposite end. A first limiter is also attached to the backplate. A slide assembly is located inside the latch box. The slide assembly has an upper latch slidably located above the guide bar, and a lower latch slidably located above the baseplate. The lower latch has a lock portal. A padlock having a shackle and a lock body with a keyhole is used as the locking device. The top of the shackle passes through the channel of the guide bar and is attached to the upper latch. The body of the padlock passes through the portal and extends into the lock slot. In another preferred embodiment, a strike box is provided. The strike box may have a strike plate with a first slot for receiving the upper latch, and a second slot for receiving the lower latch. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
     The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention. 
     FIG. 1 is a top view of the preferred embodiment of the enclosed lock device of the present invention. 
     FIG. 2 is an isometric sectional view of the embodiment of the enclosed lock device shown in FIG. 1, with the latch in the latched position and the lock in the locked position. 
     FIG. 3 is an isometric exploded view of the embodiment of the enclosed lock device shown in FIG.  1  and FIG.  2 . 
     FIGS. 4-6 are a sequence of drawings showing the progressive steps of latching and locking the device of the present invention. 
     FIG. 4 is a front view of a preferred embodiment of the enclosed lock device of the present invention in the unlatched and unlocked position. 
     FIG. 5 is a front view of a preferred embodiment of the enclosed lock device of the present invention in the latched, but unlocked position. 
     FIG. 6 is a front view of a preferred embodiment of the enclosed lock device of the present invention in the latched and locked position. 
     FIGS. 7-9 are a sequence of front sectional drawings showing the progressive steps of latching and locking the device of the present invention, as shown in 
     FIGS. 4-6, sectioned as shown in FIG.  1 . 
     FIG. 7 is a front sectional view of a preferred embodiment of the enclosed lock device of the present invention in the unlatched and unlocked position as shown in FIG. 4, sectioned as shown in FIG.  1 . 
     FIG. 8 is a front view of a preferred embodiment of the enclosed lock device of the present invention in the latched, but unlocked position as shown in FIG. 5, sectioned as shown in FIG.  1 . 
     FIG. 9 is a front view of a preferred embodiment of the enclosed lock device of the present invention in the latched and locked position as shown in FIG. 6, sectioned as shown in FIG.  1 . 
     FIG. 10 is a bottom view of a preferred embodiment of the slide assembly of the lock device of the present invention, showing the lock body protruding through the lock portal of the lower latch. 
     FIG. 11 is a bottom view of a preferred embodiment of the enclosed lock device of the present invention in the latched position. 
     FIG. 12 is a sectional end of a preferred embodiment of the enclosed lock device of the present invention, sectioned as shown in FIG.  6 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. 
     FIG. 1 is a front view, showing a first door  10  and a second door  20  which operate in complementary alignment to provide access to a storage space. It is understood, and will be understood by a person of ordinary skill in the art, that for all purposes throughout this disclosure, either first door  10  or second door  20  could be a doorframe, wall, or other stationary structure rather than a door, without changing the principles, application, meaning, or function of the presently disclosed invention. All that is necessary is that one or both of structure (first door)  10  and structure (second door)  20  is a door that opens relative to the other. Likewise, the use, content, transportability, and size of space are irrelevant to the principles, application, meaning, and function of the presently disclosed invention. Also, it will be understood by a person of ordinary skill in the art that doors are commonly made to have both left and right hand openings, depending on the application and therefore the configuration shown in the attached figures may be reversed. 
     In FIG. 1, enclosed lock device  50  is shown generally from a top view. In this figure, a latch box  60  cooperates with a strike box  120  to securely lock first door  10  to second door  20 . 
     FIG. 2 is an isometric cut-away view of a preferred embodiment of lock device  50 . FIG. 3 is an isometric explosion view of the embodiment of FIG.  2 . In FIG. 2, it is seen that latch box  60  forms an enclosure having a backplate  64  for attachment of latch box  60  to first door  10 , or doorframe, wall, or other stationary element (not shown in this view). In a preferred embodiment, latch box  60  has a baseplate  66  attached to the bottom of backplate  64 . Baseplate  66  has a lock slot  68 . In the less preferred embodiment, there is no baseplate  66 , and the opening at the bottom of latch box  60  constitutes lock slot  68 . In a preferred embodiment, latch box  60  also has an end plate  70 . In this embodiment, end plate  70  has an upper slot  72 . In a more preferred embodiment, end plate  70  also has a lower slot  74 . 
     A guide bar  76  is attached to backplate  64  as shown in FIG.  2 . In a preferred embodiment, guide bar  76  is attached to backplate  64  substantially parallel to baseplate  66 . Referring back to FIG. 3, guide bar  76  has a channel  78 . A slide assembly  80  has an upper latch  82 . In a more preferred embodiment, slide assembly  80  also has a lower latch  84 . Lower latch  84  has a lock portal  86 . A padlock  88  has a latchable shackle  90  extending from a lock body  92 . FIG. 10 is a bottom view of slide assembly  80 . As seen best in FIG. 10, a keyhole  94  in the bottom of lock body  92  receives a key  96  for releasing shackle  90  from lock body  92 . 
     Alternatively, an equivalent release mechanism such as a combination dial may be used. Lock body  92  is positioned inside lock portal  86 . Shackle  90  is attached by weld or other means to upper latch  82 . 
     In an alternative embodiment not shown, guide bar  76  is a guide rod  76 , and shackle  90  loops over guide rod  76 . In this embodiment, lower latch  84  may optionally be used to the exclusion of upper latch  82 . 
     As best seen in FIG. 2, slide assembly  80  is located inside latch box  60 . Lower latch  84  is positioned on top of baseplate  66 , in slidable relation. Upper latch  82  is located on top of guide bar  76 , in slidable relation. In the configuration of this embodiment, shackle  90  slides horizontally inside channel  78 , and lock body  92  slides horizontally inside lock slot  68 . Channel  78  limits the horizontal range of motion of slide assembly  80  in either direction. Lock body  92  is vertically movable through lock portal  86 , permitting the locking and unlocking of padlock  88  without interference with baseplate  66 . 
     Upper latch  82  extends and retracts outwardly from latch box  60  for engagement and disengagement with a strike plate in a door jamb, or with optional strike box  120 . In a preferred embodiment, upper latch  82  extends and retracts through upper slot  72  of end plate  70 , and lower latch  84  extends and retracts through lower slot  74  of end plate  70 . As best seen in FIG. 3, a rotatable link  100  is attached to backplate  64  of latch box  60 . Link  100  has an orifice  102  receivable of shackle  90  of padlock  88 . In a preferred embodiment, link  100  is pivotally attached to a link pin  104 , which is attached to backplate  64 . In another preferred embodiment, a positioning means such as a link stop  106  is attached to backplate  64  to properly align link  100  to pass through the opening between shackle  90  and lock body  92  when padlock  88  is unlocked. In another preferred embodiment, a spring member  108  is attached to a surface inside of latch box  60 , such as guide bar  76 , to assure repositioning of link  100  against link stop  106  when padlock  88  is unlocked. A person of ordinary skill in the art will appreciate that spring member  108  may be attached to guide bar  76  as shown in FIG. 2, or in various alternative configurations which will have the equivalent function and result of repositioning of link  100  against link stop  106 . 
     In another preferred embodiment, a first limiter  110  is attached inside of latch box  60  to limit the vertical movement of shackle  90 . This is necessary to permit locking of padlock  88  by vertically upward movement of lock body  92  against shackle  90 . A person of ordinary skill in the art will appreciate that first limiter  110  may be attached directly to backplate  64  as shown in FIG. 2, or in various alternative configurations which result in the equivalent function and result of restraining vertical movement of shackle  90 . For example, by virtue of the attachment of shackle  90  to upper latch  82  in this embodiment, first limiter  110  can limit the vertical movement of shackle  90  by engagement with upper latch  82 , and thus achieve the same result. In this example, first limiter  110  can be a roller, plate, or other geometry designed to engage upper latch  82  and limit upward movement. 
     In another alternative embodiment, a second limiter  112  is attached inside of latch box  60  to limit the vertical movement of lower latch  84 . Second limiter  112  can be a roller, plate, or other geometry designed to engage lower latch  84  upon upward movement. Intersection of lower latch  84  into lower slot  74  restricts movement of one end of lower latch  84 . Second limiter  112  can be attached to restrict movement of the opposite end of lower latch  84 , resulting in a more stable and secure assembly. A person of ordinary skill in the art will appreciate that second limiter  112  may be attached to guide bar  76  as shown in FIG. 2, or in various alternative configurations which result in the equivalent function and result of restraining vertical movement of lower latch  84 . For example, second limiter  112  may alternatively be attached to backplate  64 , or to lower latch  84 . 
     In the preferred embodiment, channel  78  limits the horizontal range of motion of slide assembly  80  in either direction. In another alternative embodiment, a travel limiter  114  is attached inside of latch box  60  to limit the horizontal travel of slide assembly  80  when latching door  10  and door  20  together. Travel limiter  114  limits the horizontal travel to permit alignment of shackle  90  with orifice  102 , and thus facilitates locking of padlock  88 . It is considered preferred to limit the travel of slide assembly  80  in the “latching” direction by a means other than the contact of lock body  92  with the terminal end of lock slot  68 , since that configuration would potentially interfere with the vertical movement of lock body  92  when locking padlock  88 . Travel limiter  114  may be attached to backplate  64  as shown in FIG. 2, wherein it also performs the additional function of limiting the vertical movement of upper latch  82 , further stabilizing the assembly of lock device  50 . In another preferred embodiment, first limiter  110  is positioned such that it performs the function of both first limiter  110  and of travel limiter  114 . 
     A person of ordinary skill in the art will appreciate that travel limiter  114  may be attached in various alternative configurations which have the equivalent function and result of restraining horizontal travel of slide assembly  80 . For example, travel limiter  114  may alternatively be attached to, or integral with, first limiter  110 , or with link stop  106 , or even with link  100 . In another, less preferred configuration, travel limiter  114  may be located within the strike box (discussed below) where it can engage the ends of upper latch  82  or lower latch  84  to limit the horizontal travel of slide assembly  80 . In this example, the interior of the strike box itself can act as a travel limiter. 
     In another preferred embodiment, latch box  60  has a beveled top surface  116 . In another preferred embodiment, latch box  60  has a beveled end surface  118 . The beveling of exterior surfaces  116  and  118  increases the difficulty of destroying latch box  60  by blows with a heavy sledge hammer or other device. Beveling is meant to include radiusing, chamfering, or otherwise creating a non-rectilinear exterior surface. 
     As stated above, and as shown in FIG. 1, latch box  60  cooperates with strike box  120  to securely lock first door  10  to second door  20 . Alternatively, latch box  60  may cooperate with a strike plate  124  in a door jamb that is receivable of upper latch  82  and lower latch  84 , without the need for separate strike box  120 . In FIG. 3, it is seen that strike box  120  forms an enclosure having a backplate  122  for attachment of strike box  120  to second door  20 , or doorframe, wall, or other stationary element (not shown in this view). In a preferred embodiment, strike box  120  has a strike plate  124 . In this embodiment, strike plate  124  has an upper strike slot  126  and a lower slot  128 . In a preferred embodiment, strike box  120  has a beveled top surface  130 . In another preferred embodiment, strike box  120  has a beveled end surface  132 . The beveling of exterior surfaces  130  and  132  increases the difficulty of destroying strike box  120  by blows with a heavy sledge hammer or other device. Beveling is meant to include radiusing, chamfering, or otherwise creating a non-rectilinear exterior surface. 
     In another preferred embodiment, a seal trim  134  is attached to latch box  60 . Seal trim  134  conceals and encloses the space between latch box  60  and strike box  120 . 
     Operation of the Invention 
     In a preferred embodiment of the present invention, concealed and enclosed lock device  50  is disclosed, having latch box  60  and strike box  120 . 
     FIGS. 4-6 are a sequence of drawings showing the progressive steps of latching and locking lock device  50  of the present invention. FIGS. 7-9 are a corresponding sequence of front sectional drawings showing the same progressive steps of latching and locking lock device  50 , as shown in FIGS. 4-6. FIGS. 7-9 are sectioned as shown in FIG.  1 . 
     FIG. 4 is a front view of a preferred embodiment of lock device  50  in the unlatched and unlocked position. In this view, it is seen that lock body  92  extends below latch box  60 , and is thus accessible. FIG. 7 is a front sectional view of the same embodiment of lock device  50 , shown in the same position. In this view, it is seen that shackle  90  is disengaged from lock body  92  of padlock  88 . Slide assembly  80  has been slid horizontally to the left until lock body  92  rests against the end of lock slot  68 . Upper latch  82  and lower latch  84  are disengaged from strike plate  124 , allowing free relative movement between latch box  60  and strike box  120 , and thus free movement between doors  10  and  20  (not shown in this view). In the embodiment shown, spring member  108  presses link  100  against link stop  106 . Absent spring member  108 , gravity will force link  100  against link stop  106 . In this position, link  100  and orifice  102  are located in relation to the space between uncoupled shackle  90  and lock body  92 . Even in the unlocked position, padlock  88  cannot be removed from latch box  60 . 
     FIG. 5 is a front view of a preferred embodiment of enclosed lock device  50  in the latched, but unlocked position. In this view, and as compared to FIG. 4, it is seen that lock body  92  has been moved horizontally to the right, and still extends below latch box  60 , and is thus accessible. The extension of lock body  92  below latch box  60  permits the operator to grasp lock body  92  and slide it left or right. FIG. 8 is a front sectional view of the same embodiment of the disclosed device, shown in the same position. In this view, it is again seen that slide assembly  80  has been moved horizontally to the right as compared to FIG.  7 . When lock body  92  is moved horizontally, intersection of lock body  92  with portal  86  causes coincident movement of lower latch  84 . Attachment of shackle  90  to upper latch  82  causes similar coincident movement of upper latch  82 . Horizontal travel is limited by contact between shackle  90  and the end of channel  78 . In an alternative embodiment, horizontal travel of slide assembly  80  is limited by contact between shackle  90  and travel limiter  114 . It is also seen in this view that shackle  90  remains disengaged from lock body  92  of padlock  88 . Lock body  92  has moved into a position beneath link  100 , aligning orifice  102  with the open end of shackle  90  to permit locking padlock  88 . Upper latch  82  and lower latch  84  engage strike box  120  through first slot  126  and second slot  128  respectively, prohibiting relative movement between latch box  60  and strike box  120 , and thus preventing movement between doors  10  and  20  (not shown in this view). 
     It can be seen in this view that there are a number of alternative but equivalent configurations by which limitation of the horizontal travel of slide assembly  80  may be accomplished. In particular, and as described hereinabove, first limiter  110  may be positioned so as to perform the functions of both first limiter  110  and travel limiter  114 . 
     FIG. 6 is a front view of a preferred embodiment of enclosed lock device  50  of the present invention in the latched, and locked position. In this view, and as compared to FIG. 5, it is seen that lock body  92  has been moved vertically upwards by the operator, and it no longer extends below latch box  60 . The movement of lock body  92  vertically upwards conceals lock body  92  and renders it generally inaccessible. FIG. 9 is a front sectional view of the same embodiment of the disclosed device, shown in the same position. In this view, it is again seen that by lifting lock body  92  vertically upward, the operator has caused shackle  90  to engage lock body  92 , locking padlock  88  through orifice  102  of link  100 . When the operator lifted lock body  92  vertically upwards, shackle  90  engaged first limiter  110 , limiting upward travel of shackle  90  relative to lock body  92 . Continued upward movement of lock body  92  caused lock body  92  to engage and rotate link  100  until the open end of shackle  90  passes through orifice  102 . Still further upward movement of lock body  92  resulted in locked connection of shackle  90  with lock body  92 . 
     Engagement of shackle  90  with travel limiter  114  prevents engagement of lock body  92  with the end of lock slot  68 . While there are numerous equivalent means for limiting the rightmost horizontal travel of slide assembly  80 , it is generally undesirable to limit the movement by engagement of lock body  92  with lock slot  68 , since this could result in interference with the vertical movement of lock body  92  when the operator desires to lock padlock  88 . Upper latch  82  and lower latch  84  remain engaged with strike box  120 , and now lock device  50  is locked. 
     As seen in FIG. 6, lock device  50  presents a fortress around padlock  88 . Trim seal  134  prevents any access to upper latch  82  and lower latch  84 . In the embodiment shown, latch box  60  has a beveled exterior top surface  116  and a beveled exterior end surface  118 . Also in the embodiment shown, strike box  120  has a beveled exterior top surface  130  and a beveled exterior end surface  132 . The beveling of these exterior surfaces vastly increases the difficulty of destroying latch box  60  or strike box  120  by blows with a heavy sledge hammer or other device. 
     FIG. 11 is a bottom view of the same embodiment of the disclosed device, shown in the same latched and locked position as shown in FIG.  6  and FIG.  9 . In this view it is seen that keyhole  94  is receivable of key  96  for unlocking of padlock  88 . When the operator wishes to unlock lock device  50 , keyhole  94  of padlock  88  is concealed, but accessible from the bottom of lock device  50 . By unlocking padlock  88 , lock body  92  will withdraw from shackle  90 , and extend below latch box  60 , as seen in FIG.  5 . Lock body  92  may then be grasped by the operator and moved horizontally to the left to disengage upper latch  82  and lower latch  84  from strike box  120 , as seen in FIG.  4 . 
     FIG. 12 is a sectional end of the same embodiment of the enclosed lock device of the present invention, sectioned as shown in FIG. 6, and shown again in the latched and locked position. In this figure the relationship between the components of slide assembly  80  (shackle  90 , lock body  92 , upper latch  82 , lower latch  84 ) and latch box  60  can be seen from an end view. 
     While this invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Summary:
An enclosed and concealed lock device is disclosed which provides a high degree of security. The device is resistant to tampering and to brute force destruction. One or more latches are engageable with a strike plate in a door jamb or with a strike box, which is also enclosed. A seal trim prevents access to the latch. A slide assembly having a padlock is located within a latch enclosure. An orifice on a pivotal link attaches to the shackle of the padlock. Locking the padlock raises the padlock body into the protective latch box enclosure, and prevents movement of the slide assembly. A first limiter restricts vertical movement of the shackle, allowing the padlock to be engaged by upward movement of the padlock body.