Abstract:
Presented is a device for use in detachably coupling two load bearing members which allows the transmission of linear, torsion and bending moment forces, while incorporating a security feature that allows only properly matched sets of members to be connected.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to a device for use in detachably coupling two members, which allows the transmission of linear, torsion and bending moment forces. More particularly, this invention relates to such a device used to couple trailer tongues to trailers, or trailer hitches to towing vehicles, wherein a security feature is incorporated to prevent the coupling of unmatched members or the unauthorized coupling of members not intended to be coupled.  
           [0002]    Such a device might be used, for example, to deter the theft of trailers by allowing the removal of the trailer tongue in order to render the trailer unusable, while ensuring the connection of only a tongue specifically matched to the particular trailer using the features of the disclosed device. This device could also be used, for example, to mate only particular trailer hitches to a towing vehicle in a fleet, based on the vehicle&#39;s towing capacity or suitability to a particular towing application or trailer type.  
           [0003]    Trailer hitches are added to vehicles such as automobiles and pickup trucks to provide the capability of towing another vehicle such as a trailer. Trailers are equipped with a tongue which has a socket member to grasp the trailer hitch ball while permitting pivotal movement of the trailer hitch assembly on the ball. Several devices have previously been devised which would deter unauthorized movement of the trailer. These include devices to detach the trailer tongue and devices to cover the socket member to prevent grasping of the trailer ball.  
           [0004]    Devices that allow the trailer tongue to be detached by slidably engaging the tongue into the trailer frame are susceptible to damage in use and being made unusable. If the trailer is dropped in use, the receiving or engaging member of the device can be damaged or deformed and the members can be prevented from properly engaging, thus preventing the reinstallation of the trailer tongue, and rendering the trailer unusable. These devices do not provide any security features, which allow only matched tongues to be attached to a trailer. Once these devices are defeated, the trailer can be used in a conventional manner by towing with a vehicle equipped with a ball trailer hitch. Furthermore, any unauthorized person with a like-equipped trailer tongue can attach that tongue to an equipped trailer and use it in a conventional manner.  
           [0005]    Devices that cover the socket member to prevent grasping of the trailer ball are also susceptible to being rendered unusable by deformation of the socket lip during use of the trailer. If the tongue of the trailer is allowed to drop to a hard surface, the engaging lip of the socket can be deformed, preventing the installation of the locking device. In use, these devices are easily defeated by simple cutting tools, or by a sledgehammer blow, which deforms the engaging members and allows removal of the device. Once the device is removed, the trailer is then free to be used in a conventional manner by anyone with a vehicle equipped with a ball hitch. In use, repeated dropping of the trailer tongue socket onto the hitch ball can deform the socket lip if the joint is not exactly aligned.  
           [0006]    U. S. Pat. No. 5,000,067 discloses a secure locking device, which is formed with a U-shaped member and a compatible bar for the U-shaped member. The U-shaped member has a female threaded end and female locking end. The bar has a male threaded end and a female key-receiving end. Use of ordinary cutting tools can defeat this device. Once the device is removed, the existing tongue assembly may be reinstalled using a common bolt connector, thus allowing conventional towing of the trailer.  
           [0007]    U. S. Pat. Nos. 5,348,333, 5,465,993 and 5,725,233 disclose a portable (removable) tongue for connecting a house trailer to a towing vehicle for towing the trailer from one location to another with the tongue being adapted for easy and rapid disconnection from the towing vehicle and trailer. The tongue is adapted to be attached to, and removed from, the frame that supports a house trailer. The tongue is adapted to be readily secured to the frame of the trailer for towing purposes and easily removed from the frame of the trailer while the trailer is parked in a trailer court for living purposes. These devices do not incorporate any security feature to prevent a tongue intended for use on one particular trailer to be used on other trailers similarly equipped.  
           [0008]    U. S. Pat. No. 5,794,961 discloses an anti-theft device that can be used on different size trailer tongues of the type having a socket for receiving a tow ball of a trailer hitch. While this device is less susceptible to damage incurred in use to the trailer tongue socket lip, it can quickly be defeated by the use of cutting tools, which then allows the trailer to be towed in a normal manner using a ball trailer hitch on a towing vehicle. There is no feature that disables the trailer if the device is not present or defeated.  
           [0009]    U. S. Pat. No. 5,897,126 discloses a coupling assembly for a trailer hitch which has a sleeve member mounted on the tongue of a trailer and constituting an extension thereof. A removable coupling member is detachably attached to a hitch, wherein the coupling member slidably engages with the sleeve member and is movable between a rear locking position and a forward detaching position that detaches the coupling member from the sleeve member. This device is rendered useless if the trailer is dropped and the sleeve member on the tongue is damaged or deformed, which prevents the re-installation of the coupling member. Also, there are no security features incorporated to prevent the unauthorized towing of a trailer so equipped by installing a similarly equipped tongue by unauthorized persons and towing the trailer away.  
           [0010]    U. S. Pat. No.  5 , 937 , 679  discloses an anti-theft device that locks on to the trailer coupler and covers the receptacle of the coupler, thereby preventing the insertion of a hitch ball or other towing means into the receptacle. This device is susceptible to deformation of the socket lip rendering the device useless. This device can be removed by deformation of the engaging lip of the device using cutting tools or by deformation from repeated hammer blows. Once the device is removed, the trailer can then be towed conventionally by a vehicle equipped with a ball hitch.  
           [0011]    U. S. Pat. No. 6,027,134 discloses a removable trailer tongue for use with a towing vehicle and a trailer frame equipped with hydraulic brakes. This invention fails to disclose any security features to prevent the installation of a mating tongue to then allow the trailer to be towed by a vehicle equipped with a ball hitch.  
           [0012]    In the disclosed device, the trailer is rendered unusable by removal of the tongue. Only a matched tongue can then be installed to make the trailer usable. A similarly equipped tongue could not be installed on a particular trailer unless it was matched to the specific trailer&#39;s security feature.  
         SUMMARY OF THE INVENTION  
         [0013]    Therefore, it is an objective of this invention to provide a coupling device through which linear, torsion and bending moment loads may be transferred.  
           [0014]    A further objective of this invention is to provide a security feature within a coupling device which matches a coupling member with another particular coupling member, such that these members comprise a matched coupling pair, and either of these members may not be coupled with an unmatched member.  
           [0015]    Still another objective of this invention is to provide a coupling device that allows the coupling of a trailer tongue to a trailer in such a way that only a matched tongue and trailer combination may be used together, in order to deter theft of the trailer using a similarly equipped tongue from another trailer, or to assure that the only a properly sized or equipped tongue is used with a particular trailer, for example.  
           [0016]    Yet another objective of this invention is to provide a method of rendering the trailer useless in a conventional towing manner due to the absence of the tongue and the inability to replace the tongue with a similarly equipped, but unmatched tongue from another trailer.  
           [0017]    Also another objective of this invention is to provide a device for attaching a trailer hitch to a vehicle, while incorporating a security feature such that only a particular hitch may be coupled to a vehicle to deter unauthorized use of hitches not intended for a particular vehicle, for example.  
           [0018]    These and other objectives of this invention including, but not limited to the objectives above, are met by providing a coupling device consisting of a base member assembly and an attaching member assembly. The base member assembly consists of a base member, attached to which there are two sets of a plurality of coaxially aligned tube members, suitably sized and attached to two sides of the base member, the tube members being of varied length and spacing along the tube member axis, and the front and back surfaces of the tube members being parallel to a plane aligned with the coupling direction axis, or being beveled on a plane constructed at an obtuse angle to the coupling direction axis, in such a manner as to allow coupling with the attaching member in the coupling direction. The attaching member assembly consists of an attaching member, to which there are attached two sets of a plurality of coaxially aligned tube members suitably sized and attached to two opposite sides of the member. The tube members are of a length and spacing along the tube member axis to allow a cooperating or mesh interface with the tube members of the base member assembly when the two tube sets of the base member assembly and the attaching member assembly are coaxially aligned. The end surfaces of the tube members are parallel to the end surfaces of the cooperating tube members of the base member assembly. Two coupling pins lock the coupling device together when the tube sets of the base member assembly are coaxially aligned with the tube members of the attaching member assembly, and the pin is slid through the sets of tubes to couple the two members together. An end cap behind the end set of tubes on each coupling member prevents the device from being defeated by use of coupling pins longer than the tube set length and using the external surfaces of the pin to attach to an external coupling device of some kind. The entry members of the tube member sets can be sized in such a manner that they can not be used as attachment points, due to insufficient size to carry the trailer load as it is towed. Further security may be provided by varying the internal diameter of the tube member sets and the external diameter of the coupling pins, such that only coupling pins that match the diameter of the tube member sets for the particular device can be used to successfully couple the base member and attaching member.  
           [0019]    Other objects, features, and advantages of the present invention will become apparent upon reading the following detailed description of embodiments of the invention, when taken in conjunction with the accompanying drawings and the appended claims.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    The invention is now described by way of examples with reference to the accompanying drawings in which:  
         [0021]    [0021]FIG. 1 is an exploded isometric view of the preferred embodiment of the device.  
         [0022]    [0022]FIG. 2 is an isometric view of the base member assembly of the coupling pair of the device shown in FIG. 1.  
         [0023]    [0023]FIG. 3 is a set of orthographic views of the base member shown in FIG. 1.  
         [0024]    [0024]FIG. 4 is a set of orthographic views of the attaching member shown in FIG. 1.  
         [0025]    [0025]FIG. 5 is a view of tube member end configurations.  
         [0026]    [0026]FIG. 6 is a set of orthographic views of the device in the coupled position shown in FIG. 1.  
         [0027]    [0027]FIG. 7 is an isometric view of the device in the coupled position.  
         [0028]    [0028]FIG. 8 is an exploded isometric view of an embodiment of the device where the tube member set alignment axes are planer, but not parallel.  
         [0029]    [0029]FIG. 9 is an exploded isometric view of an embodiment of the device where the tube member set alignment axes lie in parallel planes, but are not parallel.  
         [0030]    [0030]FIG. 10 is an exploded isometric view of an embodiment of the device where the tube member set alignment axes are not parallel and do not lie in parallel planes.  
         [0031]    [0031]FIG. 11 is a set of orthographic views of the embodiment of the device shown in FIG. 8.  
         [0032]    [0032]FIG. 12 is a set of orthographic views of the embodiment of the device shown in FIG. 9.  
         [0033]    [0033]FIG. 13 is a set of orthographic views of the embodiment of the device shown in FIG. 10.  
         [0034]    [0034]FIG. 14 is an isometric view of the preferred embodiment of the device incorporated into a design for a detachably coupled trailer tongue.  
         [0035]    [0035]FIG. 15 is an isometric view of the device incorporated into a design for a detachably coupled trailer hitch receiver.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0036]    Referring now to the figures, the coupling device will be more fully described. Referring to FIG. 1, the device consists of a base member assembly  10 , an attaching member assembly  11  and two locking pins  12  and  13 .  
         [0037]    Referring to FIG. 2, the base member assembly  10  consists of a base member  14 , to which two tube member sets  15  and  16 , each consisting of a plurality of tube members of equal internal diameters, are suitably attached. The members of these tube member sets  15  and  16  are coaxially aligned, and the alignment axes of each of the two sets of tube members  15  and  16  are parallel with the attachment sides of the base member  14 .  
         [0038]    As shown in FIG. 3, each alignment axis is positioned in such a manner that the axis lies at or offset externally from the mating face of the base member  14 . This allows the base member assembly  10  tube axes to be aligned with the attaching member assembly  11  tube axes without interference between the base member  14  and the attaching member  17 , as shown in FIG. 6. The tube members are of varying lengths and spacing along the alignment axis. The ends of the individual tube members of the tube member sets are perpendicular to the alignment axis, or angled on a plane through an axis parallel to the coupling direction axis and intersecting the tube member axis, or angled on a plane through an axis intersecting the tube member axis and perpendicular to the coupling direction axis, as shown in FIG. 5. The base member assembly  10  is then attached to the trailer frame by welding, using an appropriate spacer to allow clearance for assembly to the attaching member assembly  11 .  
         [0039]    The attaching member assembly  11  consists of an attaching member  17 , to which two tube member sets  18  and  19 , each consisting of a plurality of tube members of equal internal diameters, are suitably attached. These members are coaxially aligned and the alignment axes of each of the two sets of tube members are parallel with the attachment sides of the attaching member  17 . As shown in FIG. 4, each alignment axis is positioned in such a manner that the axis lies at or offset externally from the mating face of the attaching member  17 . This allows the axis of the tube member set  18  to be aligned with the corresponding base member assembly tube set  15  axis without interfering with the base member  14 , as shown in FIG. 4. The tube set members are of lengths and spacing along the alignment axis such that they mesh or cooperate with the corresponding mating tube sets of a matched base member assembly  10 . The ends of the individual tube members of the attaching tube member sets  18  and  19  are parallel to the cooperating tube members of the base tube member sets  15  and  16 , such that they match and cooperate with the tube member sets  15  and  16  of the base member assembly  10 .  
         [0040]    The security feature of the device is accomplished by the varied spacing, lengths and end surface bevels of the tube members of the tube member sets  15  and  16  of the base member assembly  10 , and the need to have a specifically matched attaching member assembly  11  in order to coaxially align both sets of tube sets of the coupling member assemblies  10  and  11 , and insert the locking pins  12  and  13  to accomplish the coupling of the device. This feature is also accomplished by varying the internal diameter of the tube member sets  15  and  16 , requiring the use of coupling pins  12  and  13  of a matched external diameters to the corresponding tube member sets  15  and  16  to accomplish the coupling of the attaching member assembly  11  to the base member assembly  10 .  
         [0041]    Other embodiments of the device consist of varying the relationship of the base tube member sets  15  and  16  alignment axes within the base member assembly, and creating a cooperating arrangement of the attaching tube member sets  18  and  19  alignment axes within the attaching member assembly  11 . FIG. 8 shows an embodiment of the device wherein the base tube member sets  15  and  16  alignment axes are coplaner, but not parallel. FIG. 9 shows an embodiment of the device wherein the base tube member sets  15  and  16  alignment axes lie in parallel planes, but are not parallel. FIG. 10 shows an embodiment of the device wherein the base tube member sets  15  and  16  are not parallel and do not lie in parallel planes.  
         [0042]    While the invention has been described in connection with certain preferred embodiments, it is not intended to limit the scope of the invention to the particular forms 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.