Abstract:
An apparatus for installation in a pickup truck box and which includes a tow beam positionably carried in a support housing positioned by a hydraulic cylinder to raise or lower the tow beam during coupling of the beam end to a truck tractor fifth wheel. Downward movement of the distal end of the beam, by the cylinder, lifts the pickup truck rear end for towing of same. Truck tractor retrieval for servicing may accordingly be accomplished by a single driver.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This is a continuation-in-part of copending patent application Ser. No. 09/843,346 Apparatus For Towing A Service Vehicle By A Truck Tractor—filed Apr. 27, 2001.  
           [0002]    The servicing of truck tractors often entails retrieving the truck tractor from a remote site for delivery to the shop performing periodic maintenance work. Present practice involves the use of two persons, one driving the service vehicle to the site of the truck tractor and accompanied by a second party to drive the truck tractor to the maintenance shop. The practice of using two workmen for the retrieval of a truck tractor to be serviced constitutes a costly effort from a man-hour standpoint over a period of several months.  
           [0003]    U.S. Pat. No. 4,555,214 discloses a towing beam fitted at its ends with king pins with one end of the beam also fitted with a hydraulic cylinder for lifting the distal end of the beam for fifth wheel engagement. A lift chain on the beam extends about the rear frame members of a truck tractor to be towed with the chain lifted by a second cylinder. The system enables the towing of an over-the-road tractor by a second like tractor both having a fifth wheel. Such a system entails the use of two semi-truck tractors which is both costly and cumbersome with limited maneuverability.  
           [0004]    U.S. Pat. No. 5,988,664 discloses a frame carried by the fifth wheel of a truck to be towed with the framework attachable to the fifth wheel of a towing truck tractor. A pivotally mounted beam is positionable by a hydraulic cylinder capable of imparting upward movement to the framework which lifts the frame of the towed tractor for towing purposes. Both vehicles must be fifth wheel equipped.  
           [0005]    U.S. Pat. No. 4,000,823 discloses a pickup truck mounted apparatus including a hydraulic cylinder for raising a tow bar engaged with the front end of the vehicle to be towed.  
           [0006]    U.S. Pat. No. 4,543,030 discloses an apparatus for placement on the tiltable fifth wheel of a truck tractor and having a towing beam adjustably mounted with a crosswise tow bar at its distal end for lifting engagement with a towed vehicle. A pair of lift cylinders supported by the tow truck frame impart motion to the adjustably carried tow beam.  
           [0007]    U.S. Pat. No. 5,845,920 shows an apparatus for towing a truck with a tow truck vehicle both equipped with fifth wheels. A tow beam is pivotally segmented and houses a hydraulic cylinder for lifting a beam segment coupled to the fifth wheel of the towed truck. A lift chain also serves to elevate the towed vehicle.  
           [0008]    Flaugh, U.S. Pat. No. 4,316,617, discloses an apparatus for securement to an automobile with the apparatus having an upright frame  10  secured to the rear bumper area of the automobile. A frame mounted winch at  86  upon retrieval of a cable  88  imparts lifting to the rear end of the automobile as the hook equipped end of the cable is supported by a boom mounted eyelet  72 . The automobile is additionally fitted with a roof mounted plate  12  and boom retainer  54  which support a pair of struts  14  for securement to frame  10 . Accordingly, automobile  94  is substantially modified for supporting the patented apparatus. Whether or not roof structures of current automobiles are of adequate strength to support a substantial portion of the automobile weight is questionable. It may be said that an automobile so altered in appearance and weight is of reduced utility for other purposes. Further, most current automobiles are of the front wheel drive type and hence are not suited for towing with the front wheels in road contact.  
           [0009]    The Aquila, U.S. Pat. No. 4,000,823, discloses a lift for use in towing a disabled automobile. A segmented beam  26  is pivotally mounted at  40  on a frame  10  in a pickup truck bed. A single acting cylinder  50  serves only to elevate a tow bar  30  for lifting of the vehicle being towed. No provision is made for extension or retraction of beam  26 .  
         SUMMARY OF THE PRESENT INVENTION  
         [0010]    The present invention is embodied in a towing apparatus suitable for installation in the box of a small service truck enabling the service truck to be towed by a semitrailer truck tractor needing servicing to a maintenance facility.  
           [0011]    The apparatus is carried in the bed of a pickup truck or other suitable vehicle with a tow beam extensible therefrom for engagement with the fifth wheel of a truck tractor to be serviced. A base of the apparatus houses hydraulic components as well as a power source to render the unitary apparatus self contained. As a pickup truck or other service vehicle becomes the towed vehicle during retrieval of a truck tractor, all may be done by one person. The apparatus is of a size and weight to be contained within a pickup truck box. The apparatus, being self contained, is readily transferable from one vehicle to another. A hydraulic cylinder positions a support member for the tow beam which, upon coupling to the fifth wheel of a towing vehicle (truck tractor), serves as a lever to lift the apparatus and the rear end of a pickup truck or other vehicle on which the base is mounted. Mechanical locks secure the tow beam against axial displacement.  
           [0012]    Important objectives include the provision of a tow apparatus which permits installation in a light duty service vehicle, such as a quarter ton pickup truck, permitting a single operator to retrieve a semitrailer truck tractor, needing servicing, from a remote location by enabling rapid attachment of the service vehicle to the truck tractor and subsequent return of both vehicles all by the single operator; the provision of an apparatus for installation in the box of a pickup truck which enables the towing of the pickup truck by a semitrailer truck tractor; the provision of an apparatus which is compact shape and unitary construction to permit permanent mounting, if so desired, in a pickup truck while leaving space in the truck box for the transport of other articles. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    In the drawings:  
         [0014]    [0014]FIG. 1 is an elevational view of the present apparatus in use to tow a service vehicle such as a pickup truck;  
         [0015]    [0015]FIG. 2 is a view similar to FIG. 1 but enlarged with fragments broken away for illustrative purposes;  
         [0016]    [0016]FIGS. 3 and 4 are perspective views of the apparatus respectively in retracted and extended positions;  
         [0017]    [0017]FIG. 5 is a plan view of the apparatus in an extended positions;  
         [0018]    [0018]FIG. 6 is a vertical sectional view taken along line  6 - 6  of FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    With continuing attention to the drawings wherein applied reference numerals indicate parts similarly hereinafter identified, the reference numeral  1  indicates generally a pickup truck, termed herein as a service vehicle, for use by the person assigned the task of retrieving the truck tractor indicated generally at  2  for periodic servicing purposes. A rearward frame portion  3  of the truck tractor is shown with a fifth wheel  4  thereon. A ramp extension  5  of the fifth wheel is typical of conventional fifth wheel structures which receives in normal use the forward end of the trailer and a king pin, all being standard items in the trucking industry.  
         [0020]    The present apparatus is indicated generally at  7  for installation as a unit in a truck box structure at  8 . While a pickup truck vehicle is illustrated as a service vehicle, upon an understanding of the invention it will be apparent that other vehicles may prove suitable for use in conjunction with the present apparatus. Bolted in place on a truck box bed  10  of a pickup truck is a welded steel base including a framework  11  including spaced apart upright members  12  of welded construction and braces at  13 . Cover plates  14  may be provided to conceal the following described hydraulic and electrical components.  
         [0021]    Carried by base  11  is a hydraulic oil tank  16  shown in FIG. 5 which serves a fluid circuit including a pump  19  powered by an electric motor  17  for powering a double acting hydraulic cylinder  20 . The hydraulic circuit additionally includes a unitized pressure relief valve and four way solenoid actuated control valve  18  serving hydraulic lines (not shown) in communication with the opposite ends of cylinder  20 . Valve  18  is in circuit with a three position toggle switch  15  for operator control of cylinder  20 . A 12 volt battery is at B.  
         [0022]    Carried by upright members  12  is a tow beam support housing  21  which is a weldment having side walls  22  in FIG. 5 and top and bottom walls  23  and  24  which form a four sided support housing for a tow beam  25  shown as a box beam. Beam support housing  21  is carried by a frame mounted pivot pin  29  permitting travel of the support housing about a horizontal axis at A along with tow beam  25  therein. A pair of side plates  26  (FIG. 4) are welded to side walls  22  of the support housing for reinforcement of same and additional bearing surface areas. The side plates extend below support housing  21 . A clevis  24 A (FIG. 6) on member  21  receives a pin  30  journaled in a bearing  31  on a piston rod  32  of hydraulic cylinder  20 . The base end of the cylinder is swingably supported for travel about a pin  34  carried by upright structures  12 . Tow beam  25  is preferably of box beam construction having an aperture at  35  for reception of a locking pin  36  to lock the beam in an extended operable position. A like aperture for pin reception is provided in a medial segment of the tow beam for locking the beam in a retracted position as shown in FIG. 3.  
         [0023]    The distal end of tow beam  25  carries a skid plate  40  with the plate supporting a king pin  42 . Prior to use tow beam  25  is lengthwise deployed from its stowed position shown in FIG. 3 to the extended position shown in FIG. 4, whereat skid plate  40  is positioned for contact with fifth wheel  4  of truck tractor  2 . For hookup of the tow beam, the same is extended and locked into place in beam support housing  21 . Upon entry of king pin  42  into the fifth wheel receptacle, the same is locked in place using conventional fifth wheel structure. Upon such locking of tow beam  25  in place within the support structure, hydraulic cylinder  20  is pressurized for extension of piston rod  32  with downward loading imparted to skid plate  40  and resultant lifting of the back end of service vehicle  1  with the tow beam serving as a second class lever with lift via pin  29 .  
         [0024]    Conventional fifth wheel construction permits limited rocking of the fifth wheel about a transversely extending horizontal axis which feature enables skid plate  40  to remain in surface engagement with the fifth wheel during lifting of the back end of service vehicle  1 .  
         [0025]    At completion of a tow, the tow beam is returned to its initial position, approximately horizontal, by retraction of piston rod  32  to unload skid plate  40  and permitting unlocking of king pin  42  from fifth wheel  4 . Prior to such unlocking, the towed vehicle  1  is in place with its rear wheels in ground contact.  
         [0026]    During towing the steering wheel of the towed vehicle is, of course, secured against movement. Tow beam  25  is locked during towing by a safety lock  43  (FIG. 2) having a pair of upright arms apertured to receive a pin  44  in a beam opening  39 . The lower end of each arm has an opening to receive a chain  45  provided with a hook at one end for engagement with a shackle as at  46  in place on truck bed  10 . Upon disengagement with the fifth wheel the tow beam locking pin  36  is removed, the beam retracted through support housing  21  and pin  36  inserted in a beam aperture to lock the beam in a forward stowed position in service vehicle box structure  8 .  
         [0027]    While we have shown but one embodiment of the invention, it will be apparent to those skilled in the art that the invention may be embodied still otherwise without departing from the spirit and scope of the claimed invention.  
         [0028]    Having thus described the invention, what is desired to be secured by a Letters Patent is: