Abstract:
A stabilizer for reducing, if not totally eliminating, swaying, fishtailing and/or jackknifing of a multi-trailer rig includes spring units that can be retrofit onto the rig between a towed unit and another unit towing that towed unit. Each of the spring units is operated by a lever-like pivot handle and the spring units are located on opposite sides of a dolly.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the general field of land vehicles, and more particularly to anti-sway devices for land vehicles. 
     2. Discussion of the Related Art 
     As more cargo is transported via land vehicles, the dangers associated with truck traffic, both to the truckers themselves and to the vehicles that share the roads with these trucks, have increased. These dangers have been further exacerbated in recent times by the trend in the trucking industry to use larger rigs, including those with multiple trailers being towed by a single tractor. 
     Large rigs, especially rigs with multiple trailers, on tight schedules often are required to operate in areas congested with a great number of small vehicles. The rigs are not nearly as maneuverable as the small vehicles, yet are often required to maneuver in tight quarters almost as though the large rig were as maneuverable as small vehicles. This is a dangerous situation that is made even more dangerous as rigs increase in size. 
     Accordingly, there is a need for a tractor/trailer rig that is maneuverable. There is a further need for a multi-trailer tractor/trailer rig that is maneuverable. 
     Still further, large rigs are subject to swaying and fishtailing as a result of road forces and/or wind forces. The swaying can become unstable and dangerous if the rig driver is not extremely skilled and attentive. Again, like the above-discussed maneuverability-related problems, the dangers associated with swaying and/or fishtailing are magnified in multi-trailer rigs. 
     Still further, the well-known problem of jackknifing is also exacerbated in multi-trailer rigs. 
     Therefore, there is a need for a stabilizing system that reduces, if not totally eliminates, swaying in tractor/trailer rigs, especially multi-trailer rigs. 
     The land vehicle art contains disclosures of systems intended to reduce swaying between trailers and the vehicles towing those trailers. The known systems generally include some elements located between the trailers and the towing vehicle. However, most of these elements are complex, difficult and expensive to install. Often, a proper set up may require factory installation. While effective, this may be too expensive or onerous for many rig drivers and/or owners. This is especially true for an existing rig that is being adapted to tow a plurality of trailers. 
     Therefore, there is a need for a stabilizer system that can be easily, quickly and inexpensively retrofit onto an existing tractor/trailer rig. 
     Still further, many of the known stabilizer systems are complex enough to be difficult and expensive to maintain and/or service. 
     Therefore, there is a need for a stabilizer that can be used on a multi-trailer rig and which is easily and inexpensively maintained and serviced. 
     PRINCIPAL OBJECTS OF THE INVENTION 
     It is a main object of the present invention to provide a stabilizer for a tractor/trailer rig that makes that rig maneuverable, especially if the rig includes a plurality of trailers. 
     It is another object of the present invention to provide a stabilizer for a tractor/trailer rig that reduces, if not completely eliminates, swaying between the towed trailers and the towing vehicle, or the trailers towing a particular vehicle in the situation of a multi-trailer rig. 
     It is another object of the present invention to provide a stabilizer for a tractor/trailer rig that is easily, quickly and inexpensively retrofit onto an existing rig. 
     It is another object of the present invention to provide a stabilizer for a multi-trailer tractor/trailer rig and which can be easily and inexpensively maintained and/or serviced. 
     SUMMARY OF THE INVENTION 
     These, and other, objects are achieved by a stabilizer for use in a tractor/trailer rig that is easily installed, even in a retrofit situation, yet is effective in reducing, if not totally eliminating, swaying, fishtailing, and jackknifing by flexibly, yet securely, connecting a towed vehicle trailer to a vehicle element towing that trailer. 
     The stabilizer establishes a force couple adjacent to a dolly which tends to dampen out the forces which create an unstable swaying or fishtailing situation. However, the stabilizer is still simple and easy to install, service and modify. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic representation illustrating a stabilizer in accordance with the teaching of this disclosure in combination with a trailer and a tractor towing the trailer. 
     FIG. 2 is a perspective view of a spring that is used in the stabilizer of the present invention. 
     FIG. 3 is a perspective view of a spring mount used in the stabilizer of the present invention. 
     FIG. 4 is a spring unit used in the stabilizer of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description and the accompanying drawings. 
     The stabilizer embodying the teaching of the present invention is easily installed on an existing rig and is thereafter easily maintained, serviced and/or modified as required. 
     Referring to FIG. 1, a portion  10  of a tractor/trailer rig is shown as including a towing tractor  12  having a tow hitch  14  thereon and a towed trailer  16  which is pivotally connected to the towing tractor  12  and is thus subject to swaying or fishtailing, especially if towed trailer  16  is one of a plurality of towed trailers. 
     As is shown in FIG. 1, towed trailer  16  has a dolly  18  thereon, the dolly extending from one end  20  of towed trailer  16  and being in the shape of a triangle to define an apex  22  which is spaced from end  20  of towed trailer  16  and which is pivotally connected to tow hitch  14  of towing tractor  12  when towed trailer  16  is attached to towing tractor  12 . It is understood that the description will refer to tractor  12 , but it will be understood by those skilled in the art based on the teaching of this disclosure that trailer  16  could be one of a plurality of towed trailers, and thus be attached to a preceding trailer, which, itself could be attached to a towing trailer, and so forth until one trailer is finally attached to the towing tractor  12 . As shown in FIG. 1, dolly  18  includes two side edges  24  and  26  which extend between end  20  of towed trailer  16  and apex  22  of dolly  18 . 
     Still referring to FIG. 1, the stabilizer of the present invention further includes two locking units  30  and  32 , one on each side edge of dolly  18 . The locking units  30  and  32  are essentially identical to each other, and thus the description of one locking unit will be understood as applying to the other locking unit as well. Each locking unit includes a base  34  mounted on an associated side edge  24  or  26  of dolly  18  and includes a forward edge  36  and a rear edge  38 . 
     Each locking unit further includes a pivot handle support  40  slidably mounted on the base  34  associated therewith to be movable from a first position adjacent to forward edge  36  of the base  34  of the respective locking unit and a second position adjacent to the rear edge  38  of the base  34  of the respective locking unit. The movable mounting includes slots defined in base  34  which slidably receive projections from handle support  40 . Each locking unit further includes a pivot handle  46  pivotally mounted on the associated pivot handle support  40 . Each pivot handle  46  including an L-shaped body  48 , a distal end  50  connected to pivot handle support  40  for movement therewith, a proximal end  52 , and an elbow  54  located between distal end  50  and proximal end  52 . The elbow  54  is located adjacent to base  34  for abutting engagement with that base  34  for a purpose which will be understood from the following disclosure. 
     The pivot handle  46  is pivotally movable in the directions indicated by double-headed arrow, designated by numeral  60  in FIG. 1, between a first configuration with proximal end  52  spaced from the associated side edge  24  and a second configuration with proximal end  52  located adjacent to the associated side edge. During this pivotal movement, elbow  54  abuttingly engages the associated side edge to define a pivot location about which the pivot handle  46  pivots in moving between the first position of the pivot handle  46  to the second position of the pivot handle  46  whereby the pivot handle  46  acts like an over-center pivot. 
     The pivot handle  46  is connected to the movable pivot handle support  40  so the pivot handle support  40  is in the first position adjacent to the forward edge  36  of base  34  of the locking unit when the pivot handle  46  is in the first configuration with proximal end  52  spaced from the associated side edge and being moved to the second position adjacent to rear edge  38  of the base  34  of the locking unit when the pivot handle  46  is in the second configuration with proximal end  52  located adjacent to the associated side edge. The pivot handle  46  is shown in the first configuration and the pivot handle support  40  is shown in the first position in FIG.  1 . 
     The stabilizer further includes two spring units  70  and  72 . Spring units  70  and  72  are identical to each other, and thus the description of one spring unit will be applicable to the other spring unit as well. Each spring unit connects an associated locking unit, either  30  or  32 , to the towing tractor. 
     As shown in FIG. 3, each spring unit  70 ,  72  includes a spring mount  74  which includes first and second U-shaped bodies  76  and  78 . Each U-shaped body  76  and  78  includes a base  80  having two outer ends  82  and  84  and two spaced apart legs  86  and  88 , with each leg having a base end, such as base end  90 , fixed to the base  80  of the U-shaped body associated therewith and a distal end  92  spaced from the base of the U-shaped body associated therewith. The base end  90  of each leg is spaced from an outer end  82  or  84  of the base end associated therewith to define a shoulder, such as shoulder  86 , adjacent to each base outer end for a purpose that will be understood from the following disclosure. 
     The first and second U-shaped bodies are shown in FIGS. 3 and 4 to be oriented with respect to each other such that the bases  80  of the U-shaped bodies are oriented at an oblique angle with respect to each other, and preferably at a right angle. As is best seen in FIG. 4, the legs of the first U-shaped body are located between the legs of the second U-shaped body and the legs of the first and second U-shaped bodies are positioned between the bases of the U-shaped bodies. The legs of the U-shaped bodies slidably engage each other as the U-shaped bodies move toward and away from each other in directions indicated by double-headed arrow, designated by the numeral  96  in FIG.  4 . 
     Each U-shaped body further includes a spring supporting foot, such as spring supporting foot  98 , on distal end  92  of each leg. 
     Each spring unit further includes a hook unit  100  fixedly attached to each base  80 . Each hook unit  100  includes a body  102  fixed at one end thereof to the base and an eye  104  on the other end of body  102 . 
     As can be seen in FIG. 4, a coil spring  110  surrounds each spring mount. As is shown in FIGS. 3 and 4, each coil spring  110  includes one end  112  positioned to abut the shoulders  86  on both U-shaped body bases, and a second end  114  positioned to abut the spring supporting ends on the legs of the U-shaped bodies as the U-shaped bodies move toward and away from each other as indicated by arrow  96  with the coil spring resisting sliding movement of the two U-shaped bodies. The ends of the spring do not always remain in contact with both the shoulders  86  and the spring supporting ends of the legs but engage an appropriate surface as necessary to resist relative movement of the U-shaped bodies. Thus, for example, if bodies  76  and  78  move away from each other, the spring supporting ends of one body will engage the spring while the shoulders of the other body will engage the opposite ends of the spring, while the opposite will occur when the U-shaped bodies move in the opposite direction. The spring force of spring  110  is selected to control the relative movement of the U-shaped bodies in accordance with the parameters required to control relative movement between tractor  12  and trailer  16  as will be understood by one skilled in the art based on the teaching of the present disclosure. 
     It is noted that assembly of unit  74  requires that the shoulders  86  or the spring supporting feet be welded in place after the spring is placed around the unit. Thus, welds are indicated in FIGS. 3 and 4, such as welds  120 ,  122  and  124 . 
     Each stabilizer further includes a first tie element, such as tie element  130 , connecting hook unit  100  on the first U-shaped body to the towing tractor  12  and a second tie element, such as tie element  132 , connecting the hook unit  100  on the second U-shaped body to the base of an associated one of the locking units and hence to the trailer  16 . Each hook unit  100  includes a body  136  having a first eye  138  fixedly connected to an eye on the hook unit  100  on one end thereof and a second eye  140  on the other end thereof for connection to either the tractor  12  or to the movable pivot handle support  40  on the dolly  18  for movement therewith. 
     As can be understood from the foregoing, as pivot handle  46  is moved from the first configuration shown in FIG. 1 to the second configuration with distal end  52  located adjacent to side edge  24 , movable pivot handle support  40  moves from adjacent to front end  36  of the mount to adjacent to rear end  38  of the mount. Since eyes  140  of the hook unit ties are connected to the spring unit and to the tractor and to the trailer, such movement of the pivot handle  46  will attempt to draw the U-shaped bodies away from each other. Such movement will be resisted by spring  110  thus setting a tension on the spring  110  and biasing the tractor  12  toward the trailer  16 . The amount of this bias is set by selection of the spring force of spring  110  and by adjusting the amount of movement of the pivot handle  46 . The pivot handle  46  need not be in the end positions discussed herein, but can be set in an intermediate position by appropriate locks either on the elbow  54  of the pivot handle  46  or by a special lock element located between the pivot handle  46  and the dolly  18 . Appropriate mounts, such as mount  140 , can be used to connect the springs to the tractor  12  or to the trailer that is towing trailer  16 . Spring mounts  150  can include appropriate hooks to engage the eyes  104  or  140 . Eyes  104  and  140  can be welded to the eyes on mounts  150  if suitable, or can simply be held in place by friction. 
     Once the bias is set on the springs  110 , any further movement of the tractor  12  with respect to the trailer  16  will be resisted by the spring units in the manner discussed above. Since the spring units are located on opposite sides of the dolly  18 , a force couple will be established about the apex  22  of the dolly  18 . This force couple will tend to resist further swaying or fishtailing of the trailer  16  with respect to the tractor  12  and thus will resist swaying and/or fishtailing. 
     It is understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangements of parts described and shown.