Abstract:
A security lock assembly includes a channel blocking frame, deadbolt and a pin-lock assembly. The channel blocking frame defines a central opening along a first axis and a pair of opposing apertures along a second axis orthogonal to the first. The deadbolt also defines an aperture or bore extending therethrough for alignment with the frame&#39;s opposing apertures when positioned at least partially within the central opening of the channel blocking frame. The pin lock assembly has an elongated shaft dimensioned to extend through opposing apertures of the lock frame and deadbolt thereby entrapping the deadbolt within the channel blocking frame. Enlarged ends of the pin lock assembly prevent unauthorized removal of the pin-lock, the deadbolt, and thus the installed lock assembly from a detachable assembly (e.g., plow). The security lock assembly when secured within an attachment channel of a plow prevents unauthorized attachment without first removing the security lock assembly.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/427,223, filed Dec. 27, 2010. The entire teachings of the above application are incorporated herein by reference. 
    
    
     BACKGROUND 
     Detachable devices, such as snow plows, trailers, and the like, are often designed for ease of attachment and removal to a vehicle. For example, a snow plow assembly may include two extending arms dimensioned and positioned to engage opposing push plate extensions disposed on a vehicle. In particular, some of the extending arms have open channels into which the push plates can be inserted. In at least some instances, the plow assembly includes a fastening feature, such as retractable latch pins that are extendable to engage apertures in the push plate extensions. When extended therethrough, the latch pins engage, entrap or otherwise attach the plow to the vehicle, such that the plow can be transported with relative ease. 
     Some detachable devices, such as snow plows, are relatively expensive devices; whereas, the push plate extensions used to engage such devices are relatively inexpensive, being perhaps 1/10 th  the cost of a plow. Thus, a thief could quickly and easily steal unattended equipment (e.g., snow plows) with a minimal investment of push plate extensions. 
     What is needed is a means to secure equipment, such as snow plow assemblies while left unattached to any vehicle to prevent unauthorized attachment and theft. 
     SUMMARY 
     It would be desirable to overcome the above mentioned shortcomings and drawbacks associated with the prior art. 
     Described herein are techniques for securing an unattached detachable device, such as a snow plow. 
     In one aspect, at least one embodiment described herein provides a security lock assembly, including a lock frame defining a central opening and further defining opposing apertures therethrough. The assembly also includes a deadbolt and a pin lock assembly. The deadbolt defines an aperture extending therethrough. The deadbolt is also dimensioned to extend at least partially within the central opening of the lock frame. The pin lock assembly has a removable end and an opposing end joined by an elongated shaft. The elongated shaft is dimensioned to extend through opposing apertures of the lock frame and deadbolt thereby entrapping the deadbolt within the locking frame. 
     In another aspect, at least one embodiment described herein provides a process for securing a detachable assembly. The process includes inserting a lock frame within an open channel of plow assembly protruding attachment arm. A portion of a deadbolt is placed through a latch pin receiving hole in the attachment arm. The lock frame is secured to the deadbolt to prevent travel of the deadbolt along its axis, thereby retaining at least a portion of the deadbolt within the latch pin receiving hole and retaining the lock frame within the open channel. A presence of the lock frame within the channel, blocks further attachment to the plow assembly protruding attachment arm. In some embodiments, the detachable assembly includes a plow blade. 
     In yet another aspect, at least one embodiment described herein provides an assembly for securing a plow. The assembly includes means for inserting a lock frame within an open channel of plow assembly protruding attachment arm. The assembly also includes means for placing a portion of a deadbolt through a latch pin receiving hole in the attachment arm. Means for securing the lock frame to the deadbolt are also included to prevent travel of the deadbolt along its axis, thereby retaining at least a portion of the deadbolt within the latch pin receiving hole and retaining the lock frame within the open channel. A presence of the lock frame within the channel, blocks further attachment to the plow assembly protruding attachment arm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features and advantages will be apparent from the following more particular description of the embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the embodiments. 
         FIG. 1  is a side view of an example of a snow plow mounting assembly. 
         FIG. 2  is a perspective view, in more detail, of an example of a plow assembly attachment arm portion of the snow plow mounting assembly shown in  FIG. 1 . 
         FIG. 3A  and  FIG. 3B  are schematic diagrams of a side view and end view, respectively, of an example embodiment of a plow lock assembly. 
         FIG. 4  is an exploded perspective view of the plow lock assembly shown in  FIG. 3A  and  FIG. 3B . 
         FIG. 5A  through  FIG. 5D  are top, end, bottom and side views, respectively, of a channel blocking portion of the plow lock assembly shown in  FIG. 3A  and  FIG. 3B . 
         FIG. 6A  through  FIG. 6D  are top, end, bottom and side views, respectively, of a deadbolt portion of the plow lock assembly shown in  FIG. 3A  and  FIG. 3B . 
         FIG. 7  is a top view of the plow lock assembly shown in  FIG. 3A  and  FIG. 3B  secured within the plow assembly attachment arm portion shown in  FIG. 2 . 
         FIG. 8  is a cross-sectional view of the secured plow lock assembly shown in  FIG. 7 . 
         FIG. 9A  and  FIG. 9B  are schematic diagrams of a side view and end view, respectively, of an example of an alternative embodiment of a plow lock assembly. 
         FIG. 10A  and  FIG. 10B  are schematic diagrams of a side view and end view, respectively, of an example of another alternative embodiment of a plow lock assembly. 
         FIG. 11A  and  FIG. 11B  are schematic diagrams of a side view and end view, respectively, of an example of another alternative embodiment of a plow lock assembly. 
         FIG. 11C  and  FIG. 11D  are schematic diagrams of a top view and bottom view, respectively, of the plow lock assembly shown in  FIG. 11A  and  FIG. 11B . 
         FIG. 12A  and  FIG. 12B  are schematic diagrams of a side view and end view, respectively, of an example of yet another alternative embodiment of a plow lock assembly. 
         FIG. 12C  and  FIG. 12D  are schematic diagrams of a top view and bottom view, respectively, of the plow lock assembly shown in  FIG. 12A  and  FIG. 12B . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a side view of an example of a snow plow mounting assembly  100 . The snow plow mounting assembly  100  includes a snow plow assembly  102  shown coupled to a plow blade  106  (shown in phantom) and a mount assembly  104  shown attached to a portion of a vehicle  110  (shown in phantom). The mount assembly  104  includes at least one forward protruding arm portion  112  for coupling to a vehicle  110  through a mount frame  114 . The arm portion  112  includes a forward-facing push plate  116  and a latch-pin receiving hole  118 . During coupling of a plow blade  106  to the vehicle  110 , at least a portion of the forward protruding arm  112  is received within a plow assembly attachment arm  108 . The plow assembly attachment arm  108  includes a retaining device, such as a retractable latch pin  164 , that can be inserted through the latch pin receiving hole  118  to form an attachment between the snow plow assembly  102 , including the plow blade  106  and the vehicle  110 . 
       FIG. 2  is a perspective view, in more detail, of an example of a plow assembly attachment arm portion  108  of the snow plow mounting assembly  100  shown in  FIG. 1 . The attachment arm portion  108  includes left and right sidewalls  150 , substantially parallel and spaced apart. A bottom edge of each of the side walls  150  is attached to a floor portion  154 , the combined sidewalls and floor portion defining an open receiving channel  156  therebetween. In the illustrative example, the left and right sidewalls  150  terminate in flared end portions  158 ,  160  at a vehicle facing end of the channel  156 , forming an open end  152 . 
     A latch mechanism  162  is securedly attached to one of the side walls  150 . The latch mechanism  162  includes a latch pin  164  slideably engaged within a latch-pin mounting bracket  166 . A guide pin  168  extends radially from a shaft of the latch pin  164 , and is slideably retained within a guiding slot  169  defined within the mounting bracket  166 . A spring  170  retained between an interior wall of the mounting bracket  166  and the pin  168  provides a biasing force urging the latch pin  164  toward the attachment arm  108 . More particularly, the biasing force of the spring urges the latch pin  164  through a pass-through hole  178  of an adjacent one of the sidewalls  150 . The latch pin  164  is configured to extend across the receiving channel  156  and in at least some embodiments, through an opposing side wall aperture  180 . When the mount assembly arm  112  is positioned within the channel, such that the latch pin-receiving hole  118  is aligned between the pass through hole  174  and the side wall aperture  180 , advancement of the latch pin  164  through the sidewall apertures  178 ,  180  secures the snow plow assembly  102  to the vehicle  110  ( FIG. 1 ). In at least some embodiments, the snow plow assembly  102  includes two such attachment arm portions  108  (e.g., left and right), each adapted for removable coupling to a respective arm  112  of a mount assembly. 
       FIG. 3A  and  FIG. 3B  are schematic diagrams of a side view and end view, respectively, of an example embodiment of a plow lock assembly  200 . The plow lock assembly  200  includes a channel-blocking frame  202 , a deadbolt  204  (e.g., an elongated rod or latch), and a pin-lock assembly  206 . The pin-lock assembly  206 , in turn, includes an elongated shaft  208 , terminated at one end in a radially enlarged, or bulbous, end portion  210 . A removable locking end, or lock body  212  is attachable at the other end of the elongated shaft  208 . The lock body  212  is also dimensionally larger than a diameter of the elongated shaft  208 . Such a pin-lock assembly  206  is sometimes referred to as a “locking hitch pin” lock, as may be used in automotive applications, for example, to secure towed devices, such as moving trailers, marine trailers, and the like. Examples of such pin-lock assemblies include pin tumbler locking no. 1480DAT, also referred to as a “stainless steel barbell lock” dimensioned for a ⅝ inch receiver opening, and no. 1472DAT for ½ inch receiver opening, each commercially available from Master Lock Company LLC of Oak Creek, Wis. 
     In the example plow lock assembly  200 , the channel-blocking frame  202  includes a channel opening  203  extending from one side to the other. In these embodiments, the channel-blocking frame  202  is an enclosed square, defining a central channel opening  203  that is also square, following a contour of the channel-blocking frame  202 . For example, the channel blocking frame  202  can be cut from hollowed square stock having a hollow interior. It is understood that other embodiments are possible in which, for example, the channel-blocking frame  202  is formed as another enclosed shape in cross-section, such as a rectangle, a triangle, and more generally as a polygon. Other cross sectional shapes are possible, such as a circles and an ellipses. For example, the channel-blocking frame  202  can be cut from cylindrical stock forming an enclosed circular cross section defining a circular opening. In some embodiments, the frame  202  is solid (e.g., cut from a solid stock) with a central aperture or bore formed therethrough, serving the purpose of the central channel opening  203 . 
     The rod, latch, or deadbolt  204  is dimensioned and shaped to extend through the central opening  203  of the channel-blocking frame  202 . In at least some embodiments, the deadbolt  204  is cylindrical in shape, having a circular shape in cross section. The deadbolt  204  can be solid or hollow. For example, the deadbolt  204  in the illustrative example is a hollow cylinder as may be formed from an elongated section of tubing. In at least some embodiments, at least a portion of the deadbolt  204  extends away from the central opening of the channel-blocking frame  202  when positioned relative thereto. In the illustrative example, a portion of the deadbolt  204  extends toward the right when viewed from one end, as shown. 
     Each of the channel-blocking frame  202  and the deadbolt  204  define respective bores therethrough. The bores are dimensioned and positioned along each of the frame  202  and the deadbolt  204 , such that the elongated shaft  208  of the pin-lock assembly  206  can pass therethrough. Preferably, bores  213 ,  214  in the channel-blocking frame  202  are also dimensioned such that they provide interference to their respective ends of the pin-lock (“barbell”) assembly  206 , preventing travel of either end of the pin-lock assembly  206  through the channel-blocking frame  202 . When assembled in this fashion, the deadbolt  204  is at least partially entrapped within the central opening of the channel-blocking frame  202 , such that a portion of the deadbolt  204  extends away from the central opening  203  of the frame  202  as best illustrated in the end view shown in  FIG. 3B . 
       FIG. 4  is an exploded perspective view of the plow lock assembly  200 . In particular, a top aperture  213  and a bottom aperture  214  are observable along top and bottom portions of the channel-blocking frame  202 , respectively. Also observable are top and bottom apertures  216 ,  218  along the deadbolt  204 . All of the apertures are circular in the illustrative example, as the elongated shaft of the pin-lock assembly  206  is also cylindrical. It is conceivable that different shaped apertures  213 ,  214 ,  216 ,  218  can be provided, and that in at least some embodiments, the shape of the apertures  213 ,  214 ,  216 ,  218  need not be the same with respect to each other and with respect to a cross-sectional shape of the elongated shaft  208 . 
       FIG. 5A  through  FIG. 5D  are top, end, bottom and side views, respectively, of the channel blocking frame  202  of the plow lock assembly  200  shown in  FIG. 3A  and  FIG. 3B . In the illustrative example, a diameter of the top aperture is D 1  and a diameter of the bottom aperture is D 2 . In at least some embodiments, D 1 =D 2 . A width of the channel-blocking frame  202  is W 1 , and a length of one of the sides of the square frame is H. The diameters of the apertures are chosen to accommodate the elongated shaft  208 , while blocking travel of either end  210 ,  212  of the pin-lock assembly  206  therethrough. Choices of the width W 1  and length, or height H, can be dictated by a particular application as will be described in more detail below. 
       FIG. 6A  through  FIG. 6D  are top, end, bottom and side views, respectively, of a deadbolt portion  204  of the plow lock assembly  200 . In the illustrative example, a diameter of the top aperture is D 4  and a diameter of the bottom aperture is D 5 . In at least some embodiments, D 4 =D 5 . A diameter of the deadbolt  204  is D 3 , and a length is L. Once again, the diameters of the apertures  216 ,  218  are chosen to accommodate the elongated shaft  208 . Choices of the deadbolt diameter D 3  and length L can be dictated by a particular application as will be described in more detail below. 
     In some embodiments, at least a portion of an outer surface of the deadbolt  204  includes a grip-enhancing feature. Such grip enhancing feature can include a knurled or otherwise abrasive finish  224 . Alternatively or in addition, the grip-enhancing feature can include a protrusion, such as a knob. In some embodiments, such a grip  224  can be fashioned by machining or casting, for example, during fabrication of the deadbolt  204 . Alternatively or in addition, such a grip  224  can be applied separately to the deadbolt  204 , for example, using an adhesive or other suitable mechanical fastener. 
       FIG. 7  is a top view of the example embodiment of the plow lock assembly  200  secured within one of the plow assembly attachment arm  108  portions ( FIG. 2 ). Generally, using one plow lock assembly  200 , even in detachable devices having more than one attachment arm portions  108 , will be a sufficient deterrent to theft. The channel-blocking frame  202  is positioned substantially within an open receiving channel  156  ( FIG. 2 ) of the attachment arm  108 . The central opening of the channel-blocking frame  202  is positioned and aligned to allow travel of the latch pin  164  therethrough, though the latch pin  164  is preferably in a retracted or otherwise open position when secured by the lock assembly  200 . The deadbolt  204  is positioned such that the end extending away from the channel-blocking frame  202  extends through the sidewall aperture  180  ( FIG. 2 ), with the other end extending through the central opening of the channel-blocking frame  202 . The top and bottom apertures  216 ,  218  of the deadbolt  204  are aligned with top and bottom apertures  213 ,  214  or the channel-blocking frame  202 . The pin-lock assembly  206  is positioned to engage each of the channel-blocking frame  202  and the deadbolt  204  as described above, extending through the aligned apertures  216 ,  218 ,  213 ,  214 . Coupling by the pin-lock assembly  206  generally prevents movement of the deadbolt  204  with respect to a cross-sectional plane of the frame  202 . Placement of the protruding end  220  of the deadbolt  204  through the sidewall aperture  118  preferentially aligns the deadbolt  204  along a travel axis of the latch pin  164 . 
     In at least some embodiments, the diameter D 3  of the deadbolt  204  is equal to or less than a diameter of the latch pin  164 , such that the deadbolt  204  provides interference, otherwise blocking travel of the latch pin  164  into the open channel of the attachment arm  108 . In at least some embodiments, the width W 1  of the channel-blocking frame  202  is slightly less than a width W 2  of the open channel of the attachment arm  108 . A tight tolerance ensures a snug fit of the channel-blocking frame  202  within the open channel preventing passage of a blade or cutting implement therebetween. 
       FIG. 8  is a cross-sectional view of the secured plow lock assembly shown in  FIG. 7 . As readily observable, a height H of the channel-blocking frame  202  is selected such that the frame  202  resides substantially within the open channel of the receiving arm  108  (i.e., not extending above a top of either side wall  150 ). In at least some embodiments, no portion of the frame extends above or otherwise beyond the open channel when secured to the attachment arm  108 . Ensuring proper dimensions, such that the frame  202  remains within the open channel when installed, prevents or otherwise blocks access to any blade or other cutting implement. 
       FIG. 9A  and  FIG. 9B  are schematic diagrams of a side view and end view, respectively, of an example of an alternative embodiment of a plow lock assembly  300 . In this example, a shield or shroud  320  is provided at a top side of the channel-blocking frame  302 . Preferably, the shroud  320  is dimensioned to extend over and otherwise block access to at least a portion of a lock body  312  of a pin-lock assembly  306 . As shown, the shroud  320  can be formed as an arch or inverted “U,” being attached at either end to the frame  302 . Such attachment can be formed by a securable means, such as a weld  322 . A side opening of the shroud  320  allows access to a key-accepting surface of the lock body  312  to allow for authorized (e.g., keyed) access, while prohibiting unauthorized access (e.g., cutting blades and the like). 
       FIG. 10A  and  FIG. 10B  are schematic diagrams of a side view and end view, respectively, of an example of another alternative embodiment of a plow lock assembly  400 . In this embodiment, a collar shield  420  is provided along at least one of the top and bottom sides of the channel-blocking frame  402  (illustrated at the bottom side). The collar shield  420  can be positioned to surround an exposed portion of the pin-lock assembly  406 , such as a one or more of a bottom end of the elongated shaft  408 , and the bottom, bulbous end  410  of the pin-lock assembly  406 . In at least some embodiments, the collar shield  420  can be entrapped between the bulbous end  410  and a bottom surface of the frame  402 , or fastened to the frame  402 , for example by welding, soldering, and/or chemical adhesive, and/or by a mechanical fastening arrangement, such as a threaded engagement. 
       FIG. 11A  and  FIG. 11B  are schematic diagrams of a side view and end view, respectively, of an example of yet another alternative embodiment of a plow lock assembly  500 . The illustrative example includes a first collar shield  520  at one end and a second collar shield  522  at another end of the channel-blocking frame  502 . In this example, the second collar shield  522  includes at least two parallel wall sections  509   a ,  509   b  (generally  509 ). The wall sections  509  extend upward from a top surface of the channel-blocking frame  502 , positioned along opposite sides of an exposed portion of an elongated shaft  508  of a pin-lock assembly  506 . In the example embodiment, the walls extend upward for a height that is sufficient to cover any exposed portion of the shaft  508 . In such a configuration the walls  509  prevent unauthorized access (e.g., by a cutting blade) to at least any exposed portion of the shaft  508 . The walls  509  can be attached to the top surface of the frame  502  by any suitable secure technique, such as a weld. Alternatively or in addition, one or more of the wall sections  509  can be formed integrally with the channel-blocking frame  502 , for example, by bending protrusions (e.g., tabs) upward that are formed within the top portion of the frame  502 . 
     A top view of the channel-blocking frame  502  is shown in  FIG. 11C . Each wall section can extend for a length along the top surface of the frame  502 , as shown. The length can be a full length of the top surface, or a shorter length, provided that the wall sections  509  provide at least some blockage to an elongated shaft  508  of the pin lock  506  when inserted through the top hole  513 . Alternatively or in addition, one or more wall sections can be provided along the top surface of the frame  502 , but not necessarily parallel with any edges of the frame  502 . 
     A bottom view of the channel blocking frame  502  is shown in  FIG. 11D . The circumferential collar shield  520  is shown encircling the bottom aperture  514 . Preferably, the collar shield  520  extends for a sufficient height above a bottom surface of the frame  502  to prevent unauthorized access (e.g., by a cutting blade) to the bottom portion of a pin-lock assembly  506  when inserted therethrough. The collar shield  520  can be attached to the frame  520  by any suitable means, such as by a weld, or a mechanical fastener, such as a threaded engagement. 
     Including one or more of the shrouds and collar shields add further measures to prevent compromise of the lock assembly when deployed. Preferably the lock assembly is made from a hardened material that is difficult to break, drill, or cut through. Such materials include metals, and particularly hardened metals, such as steel, stainless steel, tungsten and the like. 
     Placement of one locking assembly in one of the two or more attachment arms  108  of a detachable device, such as the example the snow plow assembly  102 , is generally sufficient to prevent unauthorized attachment of the snow plow assembly  102  to a mount assembly of a vehicle. As such, it provides a substantial deterrent to theft. Beneficially, the lock assembly is small, and relatively simple and inexpensive. For example, the lock assembly can be stored in a glove box or other suitable cabin compartment of a vehicle, ready to be deployed when a plow is removed from the vehicle. It is not necessary that the lock assembly be used exclusively with snow plows. It is also conceivable that such a lock assembly can be used with other detachable devices, such as construction equipment, trailers, and the like. 
       FIG. 12A  and  FIG. 12B  are schematic diagrams of a side view and end view, respectively, of an example of yet another alternative embodiment of a plow lock assembly  600 . The illustrative example includes a first collar shield  620  at one end and a second collar shield  622  at another end. In this example, the second collar shield  622  includes a circumferential wall section  609 . The wall section  609  extends upward from a top surface of a channel-blocking frame  602 . In the example embodiment, the wall extends upward for a height that is sufficient to cover any exposed portion of the shaft  608 . In such a configuration the wall  609  prevents unauthorized access (e.g., by a cutting blade) to at least any exposed portion of the shaft  608 . The wall  609  can be attached to the top surface of the frame  602  by any suitable secure technique, such as a weld. As shown, the dead bolt  604  when engaged by the pin-lock assembly  606 , protrudes  605  at least slightly from at least one side of the channel-blocking frame  602 . Such a protrusion  605  can be sufficient to extend through an adjacent wall  150  of an attachment arm  108  (e.g.,  FIG. 2 ) when mounted therein, to prevent a locking pin  164  from penetrating any portion of the wall  150 . 
     A top view of the channel-blocking frame  602  is shown in  FIG. 12C . The wall  609  can extend forming an enclosed circle, as shown. A top portion  611  of the wall  609  can be contoured, for example, to accommodate an overlapping portion of the pin-lock assembly  606  (see also  FIG. 12B ). 
     A bottom view of the channel blocking frame  602  is shown in  FIG. 12D . The circumferential collar shield  620  is shown encircling the bottom aperture  614 . Preferably, the collar shield  620  extends for a sufficient height above a bottom surface of the frame  602  to prevent unauthorized access (e.g., by a cutting blade) to the bottom portion of a pin-lock assembly  606  when inserted therethrough. The collar shield  620  can be attached to the frame  620  by any suitable means, such as by a weld, or a mechanical fastener, such as a threaded engagement. Although different features are described as being used as collar shields in the example embodiments, described herein, it is understood that any combination of such collar shields can be used in various combinations. Thus, each channel-blocking frame can be configured with one or more collar shields (e.g., along a top surface, a bottom surface, or both top and bottom surfaces). Each of the collar shields can be similar or different according to any of the collar shields described herein, and equivalents thereto. 
     One skilled in the art will realize the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting of the invention described herein. Scope of the invention is thus indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.