Abstract:
Accessories for tow trucks enable the tow truck to lift and tow heavy-duty vehicles, such as municipal buses and heavy-duty trucks. A bus adapter engages an anchor, which extends from the front or rear frame of the bus. The frame anchor may be a downwardly extending anchor member or horizontally extending anchor portion extending parallel to the frame of the bus. In an embodiment for lifting heavy duty multi-axle trucks, linear components slides into other linear component to form wheel lifts scoops. Some of the components include a hollow collar for joining the linear components Another adapter is a tow chain adapter, having therein a tow chain with a lifting hook for engaging a chain supporting frame portions of a heavy-duty vehicle such as a bus or a truck.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to tow bar accessories for heavy-duty vehicles, such as multi-axle trucks and municipal buses.  
         BACKGROUND OF THE INVENTION  
         [0002]    Wheel lifts are known for towing disabled vehicles, especially cars. These wheel lifts include manually applied extensions, forming either a box or L-shape or otherwise, coming in pairs, which encircle respective front or rear wheels of the disabled vehicle. The wheel lifts are generally extended laterally off of a crossbar, which extends from the central hydraulic probe arm of a tow truck.  
           [0003]    To lift a disabled vehicle, the probe arm is hydraulically extended rearward so that the wheel lift members are in the vicinity of the front or rear wheel pairs of the disabled vehicle. The wheel lift arms are either manually wrapped around each wheel of the respective pairs of wheels or the wheel lift arms are automatically wrapped around the wheels, such as in Applicant&#39;s issued U.S. Pat. No. 6,139,250, which describes a wheel lift for vehicles which moves both laterally and pivotably around the wheels.  
           [0004]    Older systems for lifting heavy duty motor vehicles and municipal buses include manually applied wheel lifts; however, the systems are difficult to use with heavy duty and heavy weight vehicles, such as trucks and municipal buses.  
           [0005]    For example, U.S. Pat. No. 4,904,146 of Lock describes a wheel lift with a pair of L-shaped wheel supporting cradles  14  extending in a direction perpendicular to a crossbar  26 . First, it is noted that any welded joint of two members joined at an elbow joint is inherently weak, such as L-shaped wheel supporting cradles  14  of Lock &#39; 146 . Furthermore, the fixed leg  42  of each cradle  14 , which is perpendicular to the elongated arm  40  of the L-shaped cradle  14 , is not supported by a collar, to absorb the stress of the joint joining leg  42  to elongated arm  40  of L-shaped wheel, which supports cradles  14  of Lock &#39; 146 .  
           [0006]    Furthermore, any L-shaped member, such as cradle  14  of Lock &#39; 146  is inherently heavy, because it permanently joins two components.  
           [0007]    In addition, the length of elongated arm  40  of Lock &#39; 146  is only adjustable in a direction parallel to the probe arm  12  of Lock &#39; 146 .  
           [0008]    Traditionally, heavy-duty vehicles such as multi-axle trucks or municipal buses are lifted by upwardly extending forks, which wrap around the frame of the vehicle from underneath and then lift the vehicle upward. However, such frame engagable fork members are tedious to install in place.  
         OBJECTS OF THE PRESENT INVENTION  
         [0009]    It is therefore an object of the present invention to provide heavy-duty accessories for lifting multi-axle trucks and municipal buses.  
           [0010]    It is also an object to provide modular, linear components for a wheel lift for heavy-duty vehicles, which have strong but removable joints, and which avoid the weakness of permanent L-shaped components having welded joints at their elbow joints.  
           [0011]    It is also an object of the present invention to make adjustable accessories for lifting heavy-duty vehicles.  
           [0012]    It is further an object of the present invention to improve over the disadvantages of the prior art.  
         SUMMARY OF THE INVENTION  
         [0013]    In keeping with these objects and others, which may become apparent, the present invention includes accessories for lifting and towing heavy-duty vehicles, such as municipal buses and heavy-duty trucks.  
           [0014]    In the bus-lifting embodiment, an accessory slider bar extender slides laterally from each end of the crossbar extending perpendicular to, and from, the rearward probe arm of the tow truck. This slider bar extender includes a hole at a top surface of one end thereof. The slider bar extender is hollow and generally square in cross section. Into the hole is inserted a locking tail anchor of a removable rear bus lift adapter.  
           [0015]    The rear bus adapter extends vertically upward from the sliding bar extender and includes a shoulder near a top end thereof, having a yoke, including two parallel upwardly extending wings, with a recess therebetween, for insertion of the downwardly extending bus frame anchor, which extends down from the front or rear frame of the bus. The tail of the bus lift adapter is preferably circular so that it can swivel in place within the hole in the sliding bar extender, to accurately meet with, and engage, the downwardly extending anchor member of the bus frame.  
           [0016]    Each wing of the bus lift adapter includes a respective horizontally extending through-bore, which is in positional register with another through-bore of the opposite wing, for insertion of a fastener, such as a push/pull pin with a hairpin clip, at an opposite end thereof, to lock the downwardly extending anchor member of the bus frame in place within the bus lift adapter.  
           [0017]    While comparable dimensions are appropriate, preferably, the lower tail of the bus lift adapter is about two inches in diameter. Each wing of the pair of parallel upwardly extending wings of the lift adapter are preferably about four inches in height. A one-inch recess preferably spreads the wings apart from each other.  
           [0018]    Made of hardened steel, or other suitable material, the rear lift adapter can lift multi-ton buses, which are disabled en route.  
           [0019]    In some situations, the frame of the disabled bus does not have a downwardly extending anchor member, but rather has an L-shaped member which includes a first downward extending neck part and a further horizontally extending anchor portion extending parallel to the frame of the bus. This parallel extending frame portion includes a hole, which is oriented vertically. To fit such vehicles, another bus lift adapter includes a vertically extending anchor portion, which extends above the shoulder of the adapter. The shoulder has extending upward therefrom a vertically extending pin, which engages through the hole in the horizontally extending anchor portion of the bus frame anchor. A small bore is included in the top portion of the vertically extending anchor portion for insertion of a locking pin.  
           [0020]    In the embodiment for lifting heavy duty multi-axle trucks, the present invention also includes a wheel lift with a slider arm crossbar extender, which slides into a hollow square cross sectional crossbar, which extends pivotably and generally perpendicular from the probe arm of the tow truck. A further slider crossbar extender extends at an opposite end of the transversely extending crossbar. This additional sliding crossbar extender, also lengthens the width of the crossbar. Each slider cross bar extender engages wheel slider arm member at a distal end thereof. Each wheel slider arm member includes a hollow collar, having a bore in positional register with one of the plurality of bores extending lengthwise along one of the rearward outer edges of the sliding crossbar extender. In that way, the width between the two slider arms can be adjusted. Each collar fits over each respective crossbar extender and each has extending therefrom a respective slider arm. Each slider arm is also preferably tempered steel and includes a square cross section.  
           [0021]    At the distal end of the slider arm, which extends perpendicular to the axis of the crossbar, there is provided a further plurality of holes on each side of each slider arm, for adjusting the distance between each wheel retainer arm and each crossbar extender.  
           [0022]    Each slider arm has the plurality of actually extending bores on an outer edge and a corresponding staggered plurality of bores on the opposite inner edge for discrete adjustments of a wheel retainer arm, which extends generally perpendicular to the slider arm so that the wheel retainer arm is generally parallel to the crossbar extender, thereby providing a space between which the wheels of a tire being lifted can be situated.  
           [0023]    The distal end of each slider arm slides into a respective collar of the outer wheel retainer arm. The collar includes a cross sectional member having a bore with a spring loaded pin, for engagement with one of the holes on either the outer side or the inner side of the slider arm extending perpendicular to the crossbar.  
           [0024]    The wheel retainer arm generally has a slanted surface for engaging a portion of the tire of the disabled truck. The various components of the truck slider arm are held in place by either push/pull pins, which are locked in place by hairpin clips or by spring pins. When the wheel retainer arm is positioned in place, around the outer edge of the tire, the tire is ready to be lifted and therefore the vehicle can be lifted.  
           [0025]    Because of the extra strength caused by the collars, which may also include further welding and enforcements, the slider and wheel retaining arms of the present invention can lift heavy trucks, which cannot be lifted by standard vehicle slider arms. To further hold the wheels in place, a wheel retainer ratchet and strap wraps around circumferentially around each respective tire.  
           [0026]    In a further embodiment, there is provided a crossbar extender member which extends within the crossbar and is held in place likewise by a fastener such as a push/pull pin and a hairpin clip. This adapter is one of a pair of tow chain adapters, having therein a tow chain with a lifting hook for engaging axles of a heavy-duty vehicle such as a bus or a truck. In this embodiment, the tow chain adapter extends likewise into the hollow square cross sectional crossbar. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0027]    The present invention can best be understood in connection with the accompanying drawings in which:  
         [0028]    [0028]FIG. 1 is a rear perspective view of a heavy-duty wrecker according to the present inventor;  
         [0029]    [0029]FIG. 2 is a perspective view of an exploded crossbar with a bus yoke/pin adapter;  
         [0030]    [0030]FIG. 3 is an exploded perspective view of the adapter as in FIG. 2 at the rear of a bus being towed;  
         [0031]    [0031]FIG. 4 is a perspective view of an exploded crossbar with a bus dowel/pin adapter;  
         [0032]    [0032]FIG. 5 is an exploded perspective view of the adapter as in FIG. 4 at the rear of a bus;  
         [0033]    [0033]FIG. 6 is a rear perspective view of a crossbar with an assembled lift component;  
         [0034]    [0034]FIG. 7 is a rear perspective exploded view thereof;  
         [0035]    [0035]FIG. 8 is a sectional plan view taken from FIG. 7 of a slider arm, showing dimensionally off set holes;  
         [0036]    [0036]FIG. 9 is a sectional plan view of a crossbar extender, with offset holes;  
         [0037]    [0037]FIG. 10 is a local close-up exploded detail view of a truck front tire with towing components exploded, showing the safety of the exterior assembly;  
         [0038]    [0038]FIG. 11 is a perspective view of a steering axle tire supported and strapped in place;  
         [0039]    [0039]FIG. 12 is a perspective view of an embodiment with a driving axle dual tire;  
         [0040]    [0040]FIG. 13 shows a prior art view of components on an exterior of a crossbar;  
         [0041]    [0041]FIG. 14 is a perspective view of a crossbar with an exploded view of tow hook components;  
         [0042]    [0042]FIG. 15 is a sectional cut view of the tow hook component inside, pinned to a crossbar; and  
         [0043]    [0043]FIG. 16 is an elevator view of a truck chained to a bar. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0044]    As shown in drawing FIGS.  1 - 16 , the present invention includes various adapters and accessories for lifting heavy-duty vehicles such as trucks and municipal buses which cannot be lifted by conventional automobile wheel lift components.  
         [0045]    [0045]FIG. 1 illustrates the rear of a typical wrecker, with a hydraulic probe arm  20  and crossbar  23 . Crossbar  23  will accept the various adapters and accessories to facilitate the lifting of heavy duty vehicles. The first strength-imparting feature of the present invention shown in FIG. 1 is that pin  21 , joining cross bar  23  to probe arm  20 , joins upper and lower plates  21   a  and  21   b  to hold cross bar  23  in an unencumbered configuration. For example, unlike many prior art cross bars which are cut to accommodate a joint between a cross bar and a probe arm, the pin  21  and plates  21   a  and  21   b  leave cross bar  23  intact at its joint with probe arm  20 . This keeps the inherent strength of cross bar  23  intact.  
         [0046]    In addition, as further shown in FIG. 1, pin  21  extends through a bearing sleeve having a ring of roller bearings, which allows for smooth pivoting of cross bar  23  about probe arm  21 , while pin  21  sandwiches cross bar  23  snugly between plates  21   a  and  21   b.    
         [0047]    As shown in FIGS. 1, 2 and  3 , a first embodiment of a removable rear bus lift adapter  1  is insertable at a lower end thereof within one of a pair of crossbar extenders  22  and at an upper end thereof, between a pair of attachment wings  2  which have respective holes  21  in positional register with each other. Wings  2  form an open hollow yoke holding downward extending anchor  26  of bus frame  25  therein.  
         [0048]    Wings  2  are supported by base plate  6  of adapter  1  having cylindrical tail  7  extending downward therefrom. Pin  8  is insertable within holes  21  of wings  2 .  
         [0049]    Bus lift adapter  1  swivels about tail  7  within circular hole  9  of a top wall of crossbar extender  22 , to align with downwardly extending bus frame anchor  26  of bus frame  25 . Anchor  26  fits in recess  3  between wings  2  and then is locked with push/pull pin  8 . The latter is retained with hairpin clip  4  and is loosely attached via chain  10  to base plate  6  of the yoke portion of bus lift adapter  1 .  
         [0050]    [0050]FIG. 3 shows the arrangement of the various components of a tow truck, including hydraulic probe arm  20  having a swivel coupling via swivel pin  21  to crossbar  23 . Bus lift adapter  1  is coupled to crossbar  23  by insertion of crossbar extender  22  within hollow crossbar  23 .  
         [0051]    Shown in FIG. 4 and  5 , is an alternate embodiment of bus lift adapter  11  which is compatible with busses having a different type of attachment fixture. Instead of the downwardly extending frame members  26 , as shown in FIG. 4, some bus frames  27  have horizontal anchor members  28  with a coupling hole  27 .  
         [0052]    To accommodate this arrangement shown in FIGS. 4 and 5, bus lift adapter  11  is an upper coupling element rod  14 , which is also inserted in hole  9  of each of the crossbar extenders  22 . This coupling element rod  9  of bus lift adapter  11  is shown clearly in FIG. 4. Bus lift adapter  11  also includes with base plate  12  having upper coupling rod  13  extending therefrom. Extending downward from base plate  12  is cylindrical coupling element rod  14 . Upper coupling rod  13  fits through hole  27  in horizontal anchor member  28  and is retained with a hair pin clip  15  inserted through small hole  16  of upper coupling element rod  13  of bus lift adapter  11 .  
         [0053]    [0053]FIGS. 6 through 12 illustrate another embodiment of this invention, which is a wheel lift  32  for heavy-duty trucks  30  having wheels  31 . wheel lift  32  is adjustable both laterally as well as longitudinally and it incorporates structural design features, which minimize the concentration of torsional stresses as compared with prior art automotive wheel lifts. In that regard, the present invention avoids the inherent weakness of any prior art welded joint of two members which are joined at an elbow joint, such as L-shaped wheel supporting cradles  14  of Lock &#39; 146 . In contrast, the linear bar members of the present invention are each supported by a collar which absorbs the stress of the joint joining two linear members of the heavy-duty wheel lift of the present invention.  
         [0054]    [0054]FIG. 7 is an exploded view of the components of wheel lift  32 . Crossbar  23  is shown with coupling holes  29  near the ends. These holes  29  receive push/pull pin  33  through one of holes  38  of crossbar extender  22  to adjustably couple crossbar  23  and crossbar extender  22 . Push/pull pin  33  is retained with hairpin clip  6 .  
         [0055]    A collar  36  welded to slider arm  34  is locked to one of a plurality of holes  39  via spring loaded pin  32  to provide further adjustment laterally. Reinforcement plates  35  further strengthen the joint between collar  36  and slider arm  34 .  
         [0056]    Wheel retainer arm  42  has a slanted surface  43  engage vehicle tire  31  (as in FIG. 6). Wheel retainer arm  42  includes collar  44  welded to its proximal end. Collar  44  is slid over the distal end of slider arm  34  and is engaged with any of longitudinal adjustment holes  40  via spring loaded pin  46 . This latter adjustment is to accommodate vehicle tires and wheels of various sizes. The engagement of two vehicle tires  31  on an axle is clearly shown in FIG. 6.  
         [0057]    To accommodate the lifting of heavy-duty trucks, the use of full collars  36  and  44  as well as welded reinforcement plates  35  avoid stress concentrations at joints. Also, the inserted crossbar extenders  22  within the ends of crossbar  23  add torsional rigidity to this member.  
         [0058]    [0058]FIG. 7 also shows a optional wedge adapter sleeve  47  which slides over each cross bar extender  22  to provide support and reduce the distance between the cross bar extender  22  and wheel retainer arm  42 , where small tires or flat tires are being lifted.  
         [0059]    FIGS.  8  show that slider arm  34 , illustrating a staggered offset hole pattern, wherein holes  40  in one side wall of slider arm  34  are offset from holes  40  in the opposite sidewall of slider arm  34 . This allows for minute adjustment of the distance of retainer arm  42  from crossbar extender  22  to permit wheel retainer arm  42  to abut tires of different sidewall dimensions and sizes.  
         [0060]    [0060]FIG. 9 is a sectional plan view of cross bar extender  22  which has a similar staggered hole pattern of holes  39  similar to holes  40  of slider arm  34 . This hole pattern of holes  39  allows for minute adjustability when slider arm  34  is installed onto cross bar extender  22 . Slider arm  34  can be adjusted on crossbar extender  22  to abut tires of varying tread widths, as shown in FIGS. 11 and 12.  
         [0061]    [0061]FIG. 10 is a perspective view illustrating the assembly of components on the exterior of a heavy-duty vehicle  30 . The advantage is that it provides for a safer work environment for the tow operator as he or she does not have to place him or herself in between wrecker vehicle and the heavy-duty vehicle to be towed. This is because all of the adjustable components of wheel lift  32  are installed in place outside of the outer sidewall of tire  31  to be carried.  
         [0062]    The detail view of FIG. 11 shows how a ratchet  45  and strap  46  of wheel lift  32  are used to retain tire  31  of heavy-duty vehicle  30  on the wheel lift  32 .  
         [0063]    [0063]FIG. 13 shows a prior art chain adapter fitting on an exterior of crossbar  23 , requiring relocating of accessories installed previously on cross bar  23 .  
         [0064]    In order to solve the problem of constant relocating of accessories previously installed on crossbar  23 , FIGS.  14 - 16  show the details of a chain adapter  52  of this invention. This is used for securing a tow chain  53  which wraps axle  51  of a vehicle  50 , such as a bus or truck, for towing purposes from the end of a hydraulic probe arm  20  with a crossbar  22 . The chain adapter  52  fits within the ends of crossbar  23 . Chain adapter  52  is retained in coupling holes  29  adjacent the ends of crossbar  23  via push/pull pins  33  and hair pin clips  6 .  
         [0065]    [0065]FIG. 15 is a sectional plan view illustrating the chain adapter  52  slidably installed within cross bar  23  secured by push/pull pin  33 .  
         [0066]    [0066]FIG. 16 is a detail showing the use of chain  53  around the axle  51  of vehicle  50 .  
         [0067]    As shown in FIG. 16, each of the chain adapter units  52  has a welded chain hook  56 , which secures tow chain  53 .  
         [0068]    As also shown in FIG. 16, an optional block  57  of wood or other non-scratch material protects the bumper  50   a  or body work of heavy-duty vehicle  50  from damages from abrasive scratches caused by tow chain  53 .  
         [0069]    The present invention can best be described by the foregoing description; however, it is not meant to be limiting since the invention is to be only to the scope of the invention, as noted in the appended Claims.