Abstract:
A tow-bar having a skeletonized tongue portion is described. A stopper is typically includes on the bottom portion of the tongue. A head piece having handles internal to the head piece is connected to one end of the tongue. The handles are typically positioned in a triangular arrangement. The end of the tongue, opposite the end including the head piece, includes a hinging portion that can be connected to the respective cart having the tongue. The hinging portion and the head piece include “keyed” ends so that they can connect to the tongue like puzzle pieces. These keyed portions are welded to the tongue. In this way, the pull points are not straight welds but rather keyed and welded portions thereby able to withstand typical abuse.

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to the field aircraft ground support vehicles and more particularly to a vehicle tow-bar apparatus and system. 
     II. Description of the Related Art. 
     Aircraft ground support vehicles, such as baggage carts, are often pinned together making a long train of carts. The tow-bars connecting the carts typically include an elongated tongue made from a strong metal. A donut hole is typically straight welded to one end of the tongue. Handles are also typically straight welded to the tongue adjacent the donut hole. The donut hole are used to connect to a hitch or pin on the next cart in the train. 
     Tow-bars need to be manually lifted and connected in order to connect the carts to one another. As such, the donut is constantly attached to pins and is often dropped on the ground. Furthermore, the tongue can often be run over by other vehicles. The weld between the donut and the tongue is thus typically a fatigue point in which the weld can break. 
     SUMMARY OF THE INVENTION 
     In general, the invention features a tow-bar having a skeletonized tongue portion. The skeletonization is achieved by creating several elongated channels cut across the tongue. A stopper is typically includes on the bottom portion of the tongue in order to take the brunt of the force if the tongue is dropped on the ground. An improved donut, in the form of a head piece, is connected to one end of the tongue. The head piece includes handles internal to the head piece that prevents the handles from breaking if the tongue is dropped on the ground. The handles are positioned in a triangular arrangement for ease of handling. The end of the tongue, opposite the end including the head piece, includes a hinging portion that can be connected to the respective cart having the tongue. The head piece and hinging portions are not straight-welded to the tongue. Instead, the hinging portion and the head piece include “keyed” ends so that they can connect to the tongue like puzzle pieces. These keyed portions are welded to the tongue. In this way, the pull points are not straight welds but rather keyed and welded portions thereby able to withstand abuse from dropping and being run over. 
     In general, in one aspect, the invention features a vehicle tow-bar apparatus, including a main body having an underside, a first end, a second end and a longitudinal axis, a head piece connected to the first end of the body and a hinging portion connected to the second end of the body. 
     In one implementation, the apparatus includes a plurality of elongated channels located in the main body, the channels being generally perpendicular to the longitudinal axis. 
     In another implementation, the apparatus further includes a skid plate having an arc-shape, connected generally perpendicular to the underside of the body and adjacent the first end and a bar connected to the underside of the body generally parallel to the longitudinal axis and the hinging portion 
     In another implementation, the hinging portion includes a first hinge bar connected to the main body and generally parallel to the longitudinal axis and a second hinge bar connected to the main body and generally parallel to the longitudinal axis and to the first hinge bar, wherein the first and second hinge bars include hinge holes. 
     In another implementation, the apparatus includes a male protrusion on each of the first and second hinge bars that interconnect with a respective female recess located in tapered side walls of the main body. 
     In still another implementation, the head piece further comprises abase having a male protrusion that interconnects with a corresponding female recess located in the first end of the main body. 
     In yet another implementation, the male protrusions on the hinge bars are generally perpendicular with respect to the male protrusion on the head piece. 
     In another implementation, the apparatus includes a plurality of handles in a generally triangular arrangement, the handles being located within outer edges of the head piece. 
     In another implementation, one of the plurality of handles is generally perpendicular to the longitudinal axis and at least one of the remaining plurality of handles is angled rearward with respect to the longitudinal axis. 
     In another aspect, the invention features a vehicle system, including a vehicle, a vehicle tow-bar apparatus connected to the vehicle, the apparatus having a main body having tapered sides, an underside, a first end, a second end and a longitudinal axis, a head piece having a plurality of handles positioned in a generally triangular arrangement within outer edges of the head piece, the head piece being connected to the first end of the body and a hinging portion connected to the second end of the body, wherein the head piece and the hinging portion are keyed to the main body. 
     In one implementation, the system further includes a skid plate having a generally curved shape and being connected to the underside of the main body. 
     In another implementation, the main body is skeletonized. 
     In another implementation, the vehicle tow-bar apparatus is connected to the vehicle through a connection assembly. 
     In another implementation, the vehicle is an aircraft ground support vehicle. 
     In still another aspect, the invention features an aircraft ground support tow bar apparatus, including a skeletonized main body having an underside tapered sides, a first end, a second end, a skid plate connected to the underside and a bar connected to the underside and generally parallel to the main body, the bar being adapted to connect to a connection assembly of a vehicle, a head piece keyed to the main body and having an internally arranged plurality of handles and a hinging portion having a first and s second hinge bar, the bars being keyed to and generally parallel to the main body. 
     In one implementation, the head piece is keyed to the main body through a male protrusion on the head piece being engaged with a female recess located in the first end of the main body. 
     In another implementation, the hinge bars are keyed to the main body through a male protrusion on each of the hinge bars being engaged with a respective female recess on the tapered sides of the main body. 
     In another implementation, the tapered sides taper from a narrow point adjacent the first end of the main body to a wide end having female recesses adjacent the second end of the main body. 
     In another implementation, the apparatus further includes a female recess in the first end of the main body, the recess being oriented generally perpendicular to the female recesses adjacent the second end of the main body. 
     In still another aspect, the invention features a tow-bar apparatus, including a main body having a first end and a second end and weight-reducing means located along the main body, a head piece connected to the first end having ergonomic means for handling the head piece, a hinging portion connected to the second end and means for connecting the head piece and the hinging portion to the main tongue body. 
     One advantage of the invention is that the skeletonization allows a sturdy metal to be used to make the tow-bar, and at the same time decreasing the weight of the tow-bar. 
     Another advantage of the invention is that the triangular arrangement of the handles allows the user to engage the tow-bar in a variety of ways that are natural and ergonomic to the user. 
     Another advantage of the invention is that it provides a skid plate with a large wear area in order to support and preserve the tow bar. 
     Another advantage is that the constituent components of the tow bar are keyed together similar to puzzle pieces in order to provide increased support on areas of high tension on the tow bar. 
     Other objects, advantages and capabilities of the invention will become apparent from the following description taken in conjunction with the accompanying drawings showing the preferred embodiment of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a perspective view of an embodiment of a vehicle tow-bar, 
         FIG. 2  illustrates a perspective view of constituent pieces of an embodiment of a vehicle tow-bar; 
         FIG. 3  illustrates a perspective view of a cart having an embodiment of a vehicle tow-bar; 
         FIG. 4  illustrates a top view of an embodiment of a vehicle tow-bar; 
         FIG. 5  illustrates a side view of an embodiment of a vehicle tow-bar; and 
         FIG. 6  illustrates a bottom view of an embodiment of a vehicle tow-bar. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings wherein like reference numerals designate corresponding parts throughout the several figures, reference is made first to  FIG. 1  that illustrates a perspective view of an embodiment of a vehicle tow-bar  100  having a longitudinal axis  190 . The tow-bar  100  typically includes a main tongue body (“body”)  105 , a head piece  110  and a hinging portion  115 . 
     The body  105  typically includes tapered sides  106 . The sides  106  taper from the smallest point of the body  105  to the widest point at the end of the body  105 . The body  105  also typically includes a series of elongated channels  120  cut into the body  105  and generally perpendicular to the longitudinal axis  190 . The tow-bar  100  is typically made from a sturdy metal to provide strength to the tow-bar  100 . The channels  120  remove weight from the tow-bar  100  but are arranged so that the sturdiness of the tow-bar  100  remains intact. 
     The body  105  further includes a skid plate  140  connected to the underside of the body  105 . The skid plate  140  can include a generally curved shape (as seen in further detail in FIG.  5 ). The skid plate  140  is generally used to take the brunt of the force if the tow bar  100  is dropped during use. The curved shape is a snag-free arc providing an increased wear area as the skid plate  140  contacts rough surfaces when it is dropped and often dragged. Further more, the skid plate  140  typically keeps the head  110  from contacting the ground if the tow bar  100  is dropped. The skid plate  140  is described further below with respect to FIG.  5 . The body  105  can also include a bar  145  connected to the underside of the body and generally parallel to the hinging portion  115 . The bar  145  is discussed in further detail in the description below. The head piece  110  is connected to one end of the body  105 . The head piece  110  typically has a generally includes a base  111 , generally perpendicular to the longitudinal axis  190 , and an apex  112 , the base  111  of the head piece  110  being connected to the body  105 . The apex  112  of the head piece  110  typically includes a hole  125  through which the pin on another cart (not shown) can be fit. An angled and elongated protrusion  130  is connected to the head piece  110  adjacent the hole  125 . The head piece  110  further includes a plurality of handles  135 , having corresponding recesses  137 , positioned in a generally triangular arrangement internal to the head piece  110 . One of the handles  135  is arranged generally parallel to the base  111  of the head piece  10 , which is also generally parallel to the elongated channels  120 , and therefore generally perpendicular to the longitudinal axis  190 . This parallel handle  135  is internal to the head piece  110 . The other two handles  135  are arranged along the angled sides  136  of the head piece  110 , and generally angled rearward from the longitudinal axis  190 . These side handles  135  are also internal to the head piece  110 , typically within the edges of the sides  136 . This internal arrangement of the handles  135  provides protection for the handles  135  if the tow-bar  100  is dropped. The triangular arrangement of the handles  135  also provides an ergonomic and natural positioning for a user. The triangular arrangement of the handles  135  thereby provides a variety of ways for the user to take hold of the tow-bar  100  while the user is connecting and disconnecting carts including the tow-bar  100 . 
     The hinging portion  115 , which is generally parallel to the longitudinal axis, is connected to the end of the body  105  opposite the end connected to the head piece  110 . The hinging portion  115  includes two hinge bars  116 ,  118  that interconnect with hinge pins connected to the cart (see  FIG. 3  below). Holes  117 ,  119  are included on the hinge bars  116 ,  119  in order to engage and connect to the hinge pins on the cart. One of the hinge bars  116  has a generally circular end  116   a . The other hinge bar  118  is typically longer than the hinge bar  116 . The hinge bar  118  further includes a flat side  118   a . In general, the longer hinge bar  118  used in conjunction with the flat side  118   s  allows interaction with the braking system of a ground support vehicle as described in further detail below. 
       FIG. 2  illustrates a perspective view of constituent pieces of an embodiment of a vehicle tow-bar  100 . The tow-bar  100  typically includes, as constituent pieces, the main tongue body  105 , the head piece  110  and the hinging portion  115  that includes the bars  116 ,  118 . As described above, the body generally includes the series of elongated channels  120  cut into the body  105 , the skid plate  140  connected to the underside of the body  105 , which is shown in more detail, illustrating the generally curved shape (as seen better in  FIG. 5 ) and the bar  145  connected to the underside of the body and generally parallel to the hinging portion  115 . The head piece  110  typically having the base  111 , the apex  112 , the elongated protrusion  130  adjacent the hole  125  and the plurality of handles  135  positioned in a generally triangular arrangement internal to the head piece  110  is also shown. The hinging portion  115  that is connected to the end of the body  105  opposite the end connected to the head piece  110  is also shown. The hinging portion  115  includes two hinge bars  116 ,  118  having the holes  117 ,  119 . 
     As described above, the body  105  typically includes tapered sides  106 . The sides  106  taper from the smallest point  107  of the body  105  to the widest point  108  at the end of the body  105 . The tapered sides  106  allow the smooth interconnection of the keyed constituent components, which is now described. The head piece  110  includes a male protrusion  113  having a wide end  113   a  and a narrow end  113   b . The male protrusion  113  interconnects with a female recess  114  located on the body  105  adjacent the smallest point  107  of the body  105 . The male protrusion  113  and the female recess  114  together form the key interconnecting the head piece  110  and the body  105 . 
     The bars  116 ,  118  include male protrusions  116   b ,  118   b  having a generally circular shape. The male protrusions  116   b ,  118   b  interconnect with corresponding female recesses  109  located on the widest point  108  of the tapered sides  106 . The male protrusions  116   b ,  118   b  and the female recesses  109  together form the key interconnecting the body  105  and the hinging portion  115 . 
     In general, the nature of the keyed portions between the body  105  and the head piece  110  and the body  105  and the hinging portion  115  creates a strong connection where there are natural stress points during the towing process, which include pulling twisting and bending. The narrow nature of the smallest point  107  of the body  105  allows a flush fit between the head piece  110  and the body  105  without any potential points that can catch on other objects. In contrast, the tapered nature of the sides  106  allow the sides  106  to taper into a widest point  108  to accommodate the female recesses  108 , thereby allowing a flush fit between the widest point  108  and the bars  116 ,  118 . The natural stress points, as mentioned above, naturally occur at these keyed locations. The wide to narrow shape of the male protrusion  113  and female recess  114  as well as the circular shape of the male protrusions  116   b ,  118   b  and female recesses  109  allow a secure fit of the constituent components, thereby being able to withstand the forces of the towing process. Typically the respective keyed location of the head  110  and body  105  is generally perpendicular to the keyed location of the hinged portion  115  and the body  105 . The male protrusions  113 ,  116   b ,  118   b  and respective female recesses  114 ,  109  are welded to keep them interconnected. It is understood that different shapes of the male protrusions  113 ,  116   b ,  118   b  and female recesses  114 ,  109  are contemplated. 
       FIG. 3  illustrates a perspective view of a cart  200  having an embodiment of a vehicle tow-bar  100 . The cart  200  can be any variety of ground support vehicles used in conjunction with airlines such as a baggage cart. However, it is understood that the tow bar  100  can be used in conjunction with any type of vehicle or cart requiring a tow bar. The cart typically includes a main body  205  which is shown generically as a flat bed for illustrative purposes. The cart  200  typically further includes wheels  210 . The cart  200  further includes a tow bar connection assembly  215  having hinge pins  220  that interconnect with the holes  117 ,  119  on the hinge bars  116 ,  118 . The cart  200  typically also includes a hitch assembly  225  having a hitch pin  230  that is adapted to fit through the hole on a tow bar on another cart similar to the hole  125  and tow bar  100  as shown in the figure. 
     The tow-bar  100  typically includes, as constituent pieces, the main tongue body  105 , the head piece  10  and the hinging portion  115  that includes the bars  116 ,  118 . The constituent components are keyed as described above. The body  105  generally includes the series of elongated channels  120  cut into the body  105 , the skid plate  140  connected to the underside of the body  105  and the bar  145  connected to the underside of the body and generally parallel to the hinging portion  115 . The head piece  110  typically having the base  111 , the apex  112 , the elongated protrusion  130  adjacent the hole  125  and the plurality of handles  135  positioned in a generally triangular arrangement internal to the head piece  110  is also shown. The hinging portion  115  that is connected to the end of the body  105  opposite the end connected to the head piece  110  is also shown. The hinging portion  115  includes two hinge bars  116 ,  118  having the holes  117 ,  119 . 
     In typical operation the tow bar  100  can pivot about the hinge pins  220  as needed by the operator who can engage the tow bar  100  using any of the handles  135 . The tow bar  100  can be interconnected with a hitch assembly on another cart or on a tractor or other ground support vehicle. The skid plate  140  provides support and protection for the tow bar  100 . In general, carts such as cart  200  typically include a braking system as part of the hitch assembly  215  that interacts with the tow bar  100 . The braking system typically includes a cable that interconnects with the bar  145 . As the tow bar  100  is lifted, the bar  145  pulls the cable which typically engages the braking system. Since the hinge bar  18  is longer than the hinge bar  116 , the hinge bar  118  is used as part of the braking system of the cart  200 . The flat side  118   a  on the hinge bar  118  typically engages a brake pedal  250  that is a portion of the braking system to keep the tow bar  100  oriented in an upwards position thereby keeping the braking system engaged. Having the braking system engaged while the tow bar  100  is positioned upward is useful for keeping the cart  200  secured while the cart  200  is not attached to a larger train of carts and other ground support vehicles. 
       FIG. 4  illustrates a top view of an embodiment of a vehicle tow-bar  100 . As described above, the tow-bar  100  typically includes the main tongue body  105 , the head piece  110  and the hinging portion  115  that includes the bars  116 ,  118 . The constituent components are keyed as described above. The body  105  generally includes the series of elongated channels  120  cut into the body  105 , female recess  114  and the bar  145  connected to the underside of the body and generally parallel to the hinging portion  115 . The head piece  110  typically having the base  11 , the apex  112 , the elongated protrusion  130  adjacent the hole  125  and the plurality of handles  135  positioned in a generally triangular arrangement internal to the head piece  110 , as well as male protrusion  113 , is also shown. The hinging portion  115  that is connected to the end of the body  105  opposite the end connected to the head piece  110  is also shown. 
       FIG. 5  illustrates a side view of an embodiment of a vehicle tow-bar  100 . The constituent components of the tow-bar  100  include the main tongue body  105 , the head piece  110  and the hinging portion  115  that includes the bars  116 ,  118 . The body  105  generally includes the tapered sides  106 , the skid plate  140  connected to the underside of the body and the bar  145  connected to the underside of the body and generally parallel to the hinging portion  115 . The skid plate  140  includes one or more holes  141 , which typically serve to remove weight from the skid plate  140 . As described above, the curved arc of the skid plate provides a larger surface area for wear as the tow bar  100  is dropped and dragged in normal use. The bar  145  includes a hole  146  for interconnection with a cable as part of a braking system for a cart  200  as described above with respect to FIG.  3 . The head piece  110  typically having the base  111 , the apex  112 , the elongated protrusion  130  and the plurality of handles  135  is also shown. The hinging portion  115  that is connected to the end of the body  105  opposite the end connected to the head piece  110  is also shown. The hinge bar  118  having flat side  118   a , circular male protrusion  118   b  and hole  119  is shown. 
       FIG. 6  illustrates a bottom view of an embodiment of a vehicle tow-bar  100 . The tow-bar  100  typically includes the main tongue body  105 , the head piece  110  and the hinging portion  115  that includes the bars  116 ,  118 . The constituent components are keyed as described above. The body  105  generally includes the series of elongated channels  120  cut into the body  105 , the skid plate  140  connected to the underside of the body  105  and the bar  145  connected to the underside of the body and generally parallel to the hinging portion  115 . This underside view further illustrates flattened surfaces  150  to which the skid plate and the bar  145  connect. Further recesses  160  are cut into the flattened surfaces  150  in order to skeletonize and thereby decrease overall weight of the tow bar  100  as described above. The head piece  110  typically having the base  111 , the apex  112 , the hole  125  and the plurality of handles  135  positioned in a generally triangular arrangement internal to the head piece  110  is also shown. The hinging portion  115  that is connected to the end of the body  105  opposite the end connected to the head piece  110  is also shown. 
     The foregoing is considered as illustrative only of the principles of the invention. Further, various modifications may be made of the invention without departing from the scope thereof and it is desired, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and which are set forth in the appended claims.