Abstract:
A trailer for land vehicles including bicycles has a rain drop or similar shape and two in-line seats for passengers. The seats are convertible to act alternatively as a support for cargo. The trailer includes a convex, transparent dome at the front side, and a convex, tapering tail at the back side of the trailer. The cargo area is enclosed by a rigid floor and flaccid fabric side walls. Amenities such as cup holders and pockets may be sewn into the side walls along with a reflective strip. Wheels are provided with a slight lean towards the trailer, making the distance between wheel tops smaller than between wheel bottoms. This tilt stabilizes the trailer, which already has a low center of gravity, while roll bars and multi-point seat belts help protect passengers in the event of a roll-over or other unexpected event. An optional cover for the cargo area provides protection to the cargo, whether animate or inanimate, during adverse weather.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. provisional application 60/170,707 filed Dec. 14, 1999, which names the same inventor. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention pertains to land vehicles generally, and more specifically to trailing vehicles configured for optimum performance with occupant-propelled wheeled vehicles such as bicycles and the like. Most specifically, the most preferred embodiment of the invention illustrates an aerodynamic, light-weight and safe two-passenger trailer for a bicycle. 
     2. Description of the Related Art 
     Bicycles, by their very nature and design, provide an efficient, light-weight and low-cost means of rapid transportation for humans. Bicycle pedals are acted upon by a rider using some of the strongest muscles in the human body. These muscles are well-adapted to provide many repetitions of driving force, while the chain and sprockets typically found in a bicycle enable the rider to provide an optimum combination of force and repetition rate. Wheels with bearings enable the rider to coast without exertion, and thereby derive full benefit from inertia, gravity, tail winds, and the like. Bicycles are most commonly provided with two in-line wheels and a frame extending therebetween, making the bicycle relatively long and tall, but also very narrow. Consequently, a bicycle requires minimal space for storage when not in use, and the bicycle will also present almost no aerodynamic drag when in use. 
     Aerodynamic drag is a function of the square of the relative velocity between the bicycle and surrounding air, and the coefficient of drag is representative of the aerodynamic efficiency of surfaces which interact with the air during motion. With a bicycle and rider, the vast majority of drag comes from the rider&#39;s own body interacting with the surrounding air. Unfortunately, at even moderate speeds the interaction with air consumes the majority of power provided by the bicycle rider. Consequently, it is highly desirable to not add additional loads to the bicycle rider, since these loads can very adversely impact the speeds and advantages normally attained with a bicycle. 
     Owing to its narrow stature, there is very limited space available on a bicycle for carrying cargo. Cargo must usually be carried by backpack, bicycle packs including tire, basket or other similar packs and baskets, each which either are extremely limited in cargo capacity or which tend to add a great deal of bulk and air resistance to a bicycle. Furthermore, there is no space available for the safe transport of additional passengers. Bicycle seats for additional passengers tend to be very high and unbalanced, which can undesirably lead to serious accidents or injuries. 
     As an alternative to supporting cargo and additional persons upon the bicycle, trailers have been designed for attachment to the bicycle that may be towed behind the bicycle. These trailers offer a number of distinct advantages over bicycle mounted carriers, and may include a low center of gravity, a separate wheel support, “drafting” behind the cyclist to take advantage of the airstream about the cyclist, easy separation from the bicycle when not required, and flexibility regarding the size or shape of cargo and passengers. In some cases, the trailer may further be designed for particular stability or ruggedness not inherent in the design of a bicycle. 
     Undesirably, and as aforementioned, there is only limited power available from a cyclist. This power is very precious and is desirably conserved for transportation in order to make the ride as pleasant and enjoyable as possible. The power is not preferred for dragging an additional load. 
     Exemplary of the trailers designed for use with bicycles are U.S. Pat. No. 5,641,173 to Cobb, Verd Jr. and also Des. 3470,429 to Smith. In the Cobb patent, an aerodynamically designed trailer has a trailer tongue coupling forward through a universal joint to a bicycle seat post and a single wheel aft of a cargo carrier. The cargo carrier has a vertically extending aerodynamic design which is adaptable to carry either a single child in a seat, a clothes bar that might be used to hang various clothing or garment bags and the like, or a cargo shelf for supporting other diverse cargo. Unfortunately, while the Cobb patent may serve the purpose of carrying clothes or other narrow cargo, the Cobb design is a relatively tall and narrow configuration similar to the bicycle. This design gains little additional space over that already available, for example from a bag hanging from the top bar between seat post and handle bars. Furthermore, the Cobb design attaches at the sea post, which is very high on the bicycle, and includes only a single wheel for the trailer. While this design may suffice when used with ordinary durable cargo, the design is not adequate for those applications where the trailer is used to transport fragile or precious cargo or persons. This is due to the fact that, should the cyclist unexpectedly tip the bicycle, there is nothing to uncouple the carrier from the bicycle or support it independently. Consequently, a child being carried in the trailer will also be dropped to the ground in a violent manner when the cyclist goes down, which is highly undesirable. Should the cyclist leave the bicycle unattended even briefly, motion within the trailer may readily topple both the bicycle and the trailer. Furthermore, the Cobb trailer will only carry a single child, and even then in a backward position, which can be very disorienting and unsettling to some children. 
     The Smith design represents a much more common configuration for a bicycle trailer, but likewise serves to illustrate the difficult trade-offs that are made in the prior art trailers designed for bicycles. In the Smith patent, the carrier is illustrated having a transparent cover, a wide seat which might accommodate two smaller children in a side-by-side arrangement or one larger child, and a wide and stable wheel base. The lower center of gravity and wider wheel base serve to protect the child or children in the trailer, even if the cyclist or bicycle should topple, since the wide wheel base will be relatively difficult to topple. Unfortunately, the wide wheel base also presents a much larger front surface for interacting with the air, and a greater coefficient of drag. Drag is proportional to the drag coefficient, frontal area and the square of vehicle speed. With a larger front surface and coefficient of drag, the drag is much greater. Unfortunately, the trailer adds a great burden onto the cyclist, preventing a cyclist with the trailers of this design from keeping pace with bicycles without trailers. What is desired then is a trailer capable of transporting more than one child, while protecting the child and still preserving low weight and aerodynamic efficiency. 
     SUMMARY OF THE INVENTION 
     In a first manifestation, the invention is a trailer which is aerodynamically efficient when towed behind a land vehicle. A carriage within which cargo including persons may be transported has a front, a back spaced from the front, and sides extending from front to back and forming a space for cargo. A shield interposed between carriage and land vehicle protects cargo from hazards during transit. The shield has a convex shape with an apex and a base, the apex displaced from base in a direction parallel to the direction of travel and towards the land vehicle. A tail member has a convex shape with a base adjacent the carriage and an apex displaced from the base in a direction away from the land vehicle. A wheel set moves and maintains the carriage, shield and tail member spaced from the ground. A tongue maintains the trailer spaced a predictable distance from the land vehicle. 
     In a second manifestation, the invention is a means for transporting cargo aerodynamically behind a bicycle propelled by a cyclist. A means is provided for supporting and enclosing cargo and has a main cargo space, a leading apex, a leading convex surface between the main cargo space and leading apex, a trailing apex, a trailing convex surface between the main cargo space and the trailing apex, and an aerodynamic transition between the leading and trailing apex. A means transmits light reflected from enclosed cargo to cyclist. Another means separates the enclosing means from a surface upon which bicycle and cargo transporting means travel. A means also couples bicycle to enclosing means. 
     In a third manifestation, the invention is a bicycle trailer. A polyhedral passenger compartment which is generally elliptical in cross-section is taller than wide and has a rigid plastic floor, flaccid side walls, and a generally elliptical frame support about which the passenger compartment is formed. A transparent, convex shield is provided at one end of the polyhedral passenger compartment and a flaccid convex tail cover is provided at a second end of the polyhedral passenger compartment opposite the transparent shield. First and second seats that are in line with each other are located within the passenger compartment. These seats are convertible between passenger seating and cargo supporting. First and second wheels and a frame for supporting the polyhedral passenger compartment are displaced from the ground, the first wheel defining a first plane through which a surface of the first wheel surface rotates and second wheel defining a second plane through which a surface of the second wheel rotates, the first and second planes which are not parallel with each other. 
     OBJECTS OF THE INVENTION 
     A first object of the invention is to provide a stable, safe and secure means for a cyclist to transport children. A second object of the invention is to enable the cyclist to carry either cargo, one child with cargo, or two children in a stable, safe and secure manner. A third object of the invention is to provide a stable support base which prevents toppling, and a coupling to a bicycle or other land vehicle which uncouples rotation or tipping of the towing vehicle from the trailer. Another object of the invention is to provide sight windows to enable the cyclist to observe the status of the cargo and allow animate cargo to view their surroundings during transit. A further object is to enable the cyclist to transport cargo and children without sacrificing efficiency during transport. Yet another object of the invention is to enable children to enjoy riding in the trailer, regardless of weather conditions. A further object of the invention is to provide for small amenities that help to ensure the safety of the children while also making the ride more pleasurable. These and other objects of the invention are achieved in the preferred embodiment of the invention, which will best understood when considered in association with the appended drawing figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a preferred embodiment trailer designed in accord with the teachings of the invention with the optional weather shield removed, from a right side plan view. 
     FIG. 2 illustrates the preferred embodiment trailer of FIG. 1 from a left side plan view with the optional weather shield installed. 
     FIG. 3 illustrates the preferred embodiment trailer of FIGS. 1 and 2 from a back, plan view. 
     FIG. 4 illustrates the preferred embodiment trailer of FIGS. 1-3 from a top plan view, with the flaccid exterior  20  and seats  24   a ,  24   b  removed, to reveal the underlying frame  22 . 
     FIG. 5 illustrates the preferred embodiment trailer  10  from a side view with flaccid exterior and wheel set removed for clarity of the seat structure and operation. 
     FIGS. 6-8 illustrate a preferred clamp having utility in the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment trailer  10  includes a carriage  12  for carrying children or other animate or inanimate cargo, a tongue  14  for connecting carriage  12  to a bicycle or other land vehicle, and a wheel set  15  for providing mobility to carriage  12 . Carriage  12  includes a front aerodynamic shield  16 , a body member  18  including a floor  19 , a tail member  20 , and a frame  22 . The shape of carriage  12  may vary from the general shape illustrated, but the preferred embodiment is hollow and generally cylindrical with closed ends and a partially open top. To obtain the lowest aerodynamic drag, carriage  12  may be similar in shape to a raindrop with shield  16  taking the shape of the leading, more rounded surface or bottom of a raindrop, body member  18  taking the shape of the gently tapering body of a raindrop, and tail member  20  taking the more pointed shape of the top or trailing edge of a raindrop. 
     The length of carriage  12  may also vary from one design to the next. However, for normal use with a bicycle, the length of carriage  12  will preferably range from approximately eighty-four inches to fifty-four inches, which allows space for two children and some cargo. Greater lengths undesirably add weight and cost, increase the difficulty of storage, and adversely affect safety during crossing of intersections and the like. Shorter lengths undesirably limit the capacity of carriage  12  to carry children and cargo. In the most preferred embodiment, the length of carriage  12  is sixty-four inches. 
     Aerodynamic shield  16  may be designed from one of a variety of geometric shapes, including rectangular polyhedrons, oval, elliptical or circular polygons, a hollow semi-sphere, a triangular polyhedron or other object. Preferably, shield  16  will be convex, to smoothly direct air flow in a laminar manner about the leading edge of carriage  12  with a minimum of turbulence and drag. Shield  16  will most preferably be similar in shape to the bottom portion of a raindrop. The height of shield  16 , from a bottom edge to top edge, is not restricted to any particular dimension, but will preferably range from approximately thirty-six inches to twenty-two inches for the lengths of carriage  12  noted herein above. In the most preferred embodiment, the height of shield  16  is approximately twenty-seven inches. The width of shield  16 , from the left side to the right side measured along a line generally parallel to the ground, is also not restricted, but will preferably range from approximately twenty-four inches to twelve inches. In the most preferred embodiment, the width will be approximately sixteen and one-half inches. As can be readily seen from the drawing figures and the numbers herein, shield  16  will most preferably be higher than wide, which allows trailer  10  to track generally within the airstream created by a cyclist. This greatly reduces the drag created by trailer  10 . Owing to the aerodynamic generally convex shape of shield  16 , the coefficient of drag is similarly quite low, reducing the drag of the present invention greatly over the more box-like configurations such as illustrated by the Smith patent referenced herein above. 
     Shield  16  may be made of any variety of materials. However, shield  16  is preferably unbreakable to protect and preserve the safety of any animate cargo, such as children and animals, and transparent to allow viewing therethrough. It is infrequent, but not unheard of, for rocks, branches and other debris to be thrown from the tires of the towing land vehicle, even when this vehicle is a bicycle. This debris should bounce off of shield  16  in the way of any windshield or the like known in the art of land vehicles. However, the material will also preferably preserve the low weight of trailer  10  to not unduly load down a cyclist when starting into motion or when climbing hills. Preferably the material will be transparent or translucent, to allow any trailer passengers good viewing therethrough, while also most preferably allowing a cyclist to view the trailer passengers as well, to visually check on their safety and well-being. The material may be unbreakable glasses or ceramics, hard or flexible plastic, fabric, composites, metals or other suitable material. In the most preferred embodiment, the material used in shield  16  is PETG (polyethylene terephthalate glycolate), owing to cost, transparency, durability, and working characteristics, though polycarbonates, acrylics, vinyls, copolymers and other similar or diverse materials having the desired characteristics are also contemplated. 
     The shape of body member  18  may also vary from one design to the next. The shape may be generally that of a rectangular polyhedron, a cylinder, sphere, or other suitable shape that allows space for passengers or cargo. However, preferably, the shape of the body member  18  will be cylindrical or slightly conical. The shape of the body member  18  may most preferably be similar in shape to the body, or middle portion, of a raindrop for the greatest aerodynamic efficiency. Nevertheless, the tapering of the body of a raindrop does add somewhat to manufacturing and, consequently, adds to the cost, as well as adversely impacting the amount of cargo or size of children that may be accommodated. These opposing factors must be considered in the design of body member  18 . 
     Body member  18  will also most preferably include an open top for entrance into and exit from within. At least one chair  24  will also preferably be provided. Body member  18  may include more than one seat, such as a first seat  24   a  and a second seat  24   b  as illustrated in the preferred embodiment. One or more chairs  24  may be secured within body member  18  by any suitable securing mechanism. In the preferred embodiment and best illustrated in FIG. 5, chairs  24   a ,  24   b  include fasteners such as snaps  82 ,  83 ,  382 ,  383  that allow chairs  24   a ,  24   b  to be positioned either upright for human use, or laid down for other cargo. In an upright position, as shown by the figure, front seat  24   a  is attached to lower side rod  30  through two fastening straps  180 ,  280 . These fastening straps  180 ,  280  may be terminated in a number of alternative ways, but most preferably snaps may be used which allow seat  24   a  to be removed when needed, for such occasions as cleaning, rearranging for special cargo, and the like. The use of two straps  180 ,  280  and snaps anchored to lower side rod  30  ensure that seat bottom  84  may be reasonably stretched so as to not unduly deform, even where seat bottom  84  is merely constructed from fabric. Similarly, strap  80  fastens to snap  82  to keep seat back  86  in an upright position. In a like manner, seat  24   b  is anchored through straps  380 ,  480  and  580  to lower and upper side rods  30 ,  32 . When two children are to be carried within carriage  12 , seats  24   a ,  24   b  will most preferably be in the positions shown in FIG.  5 . However, when only one child is to be carried, or cargo which would desirably be rested on a relatively flat surface such as provided for by seat bottom  384 , then seat back  386  may be lowered by releasing strap  380  from snap  382  and lowering seat back  386  as shown by the dashed line until strap  380  may be snapped to snap  383 . Should no children require transport, front seat back  86  may similarly be lowered along the dashed line shown in FIG. 5, and strap  80  snapped into snap  83 . In this configuration of seats  24   a ,  24   b , with both seat backs lowered, a large flat surface is provided for carrying cargo. Seat belts  90  and  92  will most preferably also be provided, and these belts  90 ,  92  may also be attached through straps  80 ,  180 ,  280 ,  380 ,  480 ,  580 , though other points of attachment may also be provided at the option of the designer. 
     Body member  18  will preferably be long enough to hold at least two small children, while not excessively extending the length of trailer  10  to an unsafe or hard-to-transport length. This length may preferably range from seventy-eight inches to fifty-two inches. More preferably, the length will range from sixty-six inches to fifty-six inches, and most preferably the length will be approximately fifty-eight inches. The inside width of body member  18  may range from twenty-eight inches to less than twelve inches, depending upon the design and objectives. However, preferably, the width of body member  18  will range from twenty inches to fourteen inches, and most preferably will be approximately sixteen and one-half inches. This width, when used in combination with the most preferred height, establishes an excellent transposition into the airstream created by a cyclist, thereby reducing the total drag of trailer  10 , while also comfortably accommodating children and a variety of cargo. 
     Body member  18  may be manufactured from a variety of materials. The material should be lightweight and resilient, and preferably not be easily crushable or punctured, to help protect cargo. The material may be aluminum, hard plastic, or other suitable material, though most preferably will be selected from among a number of lightweight and durable fabrics or films having characteristics similar to nylon and polyester. If woven fabrics are used, which offer excellent strength and tear-resistance for minimal weight, they will most preferably be waterproofed to prevent the passage of moisture therethrough during rain or in the event a puddle or other water body is traversed. One advantage of using a fabric is the ease at which additional amenities, such as cup holders or other pouches or pockets may be provided. In the most preferred embodiment, a woven fabric is used and a special reflective strip  58  such as manufactured by Minnesota Mining and Manufacturing for use as an outdoor reflector is adhered to the fabric, either adhesively, or through sewing or other suitable means. The floor  19  of body member  18  in the preferred embodiment is manufactured from solid, rigid plastic to provide greater protection against road hazards that might otherwise harm cargo. 
     To reduce drag, and similar to shield  16  and body member  18 , tail member  20  should be aerodynamic. Tail member  20  may be approximately conical or have other suitable shape, though most preferably it will resemble the top portion of a raindrop to be most aerodynamic. As with body member  18 , the cargo capacity and coefficient of drag tend to work in opposition, since a larger, narrower tail member  20  will require more room for transport and more time to cross an intersection, and will also require more material for fabrication, while providing little extra cargo space. Tail member  20  may be manufactured from the same or similar material to either that of body member  18  or shield  16 . This material, as aforementioned, may be aluminum, hard plastic, or other suitable material, vacuum formed plastic such as PETG, or the like. However, most preferably, tail member  20  is made from the same contiguous piece of woven fabric as body member  18 , thereby simplifying manufacture and keeping parts counts lower. Longitudinal tail curve  29  is provided to add framework for supporting fabric in a desired configuration. 
     The length, width and height of tail member  20  may also vary, depending upon design objectives. The length, from the tip of the cone to the base of the cone, may range from approximately twenty inches to less than two inches. Preferably, the length will range from approximately eighteen inches to six inches, Most preferably, the length will be approximately twelve inches. The width of the base of the cone in the preferred embodiment may range from approximately thirty-six inches to less than ten inches. Preferably, the width will range from approximately twenty-four inches to twelve inches, and will most preferably be approximately sixteen and one-half inches. The height, from the lowest edge to the highest edge, may range from approximately forty-eight inches to less than twenty inches. Preferably, the height will range from approximately thirty-six inches to twenty-two inches. Most preferably, the height will be approximately twenty-seven inches. 
     Frame  22  may be manufactured from a wide variety of materials, depending upon various design objectives, ratings and dimensions. Frame  22  in the preferred embodiment will be rated to support more than 100 pounds, and will most preferably be extremely light weight and corrosion resistant. Consequently, frame  22  will preferably be made from aluminum tubing, though other materials including copper, steel, plastics or other suitable material may be used as will be apparent to a designer in view of the present disclosure. Frame  22  in the preferred embodiment includes a front rod  27 , a tail rod  28 , longitudinal tail curve  29 , a lower side rod  30 , an upper side rod  32 , a first axle assembly rod  34  and a second axle assembly rod  36 . These rods  27 ,  28 ,  29 ,  30 ,  32 ,  34 , and  36  may be hollow or solid, though they will preferably be hollow to maintain strength to weight ratios at a maximum. The rods may be bent into different shapes as described below, and may have different or varying diameters. The diameter will preferably range from two inches to one-quarter inch. Smaller diameters tend to lose strength, while larger diameters add cost, size and weight that may be undesirable. Preferably, the diameter will range from one and one-half inch to one-half inch. In the most preferred embodiment, the diameter of these rods is approximately one inch. 
     Front rod  27  may be attached, using any suitable attachment mechanism, to shield  16 , and tail rod  28  will also preferably be attached to tail member  20 . Rivets, screws, bolts, adhesives and other known fasteners may be used for each attachment, as long as the fasteners provide durable attachment to prevent shield  16  from separating from rod  27  and tail member  20  from separating from tail rod  28  during use. Preferably, front rod  27  is oval in shape, and corresponds in size and shape to the edge of shield  16 . In the most preferred embodiment, which has been designed for maximum cargo capacity and minimum manufacturing costs, the circumference of both front rod  27  and tail rod  28  will be approximately eighty-seven inches. The unique oval design of front rod  27  and tail rod  28  provides excellent protection to passengers or other cargo in the event trailer  10  should roll over or be impacted from the side, top or bottom. In fact, rods  27 ,  28  act as roll bars. 
     Lower side rod  30 , visible in FIG. 5, and upper side rod  32  extend longitudinally between front rod  27  and tail rod  28 , and may be attached using any suitable attachment mechanism such as welding or mechanical fastening. In the most preferred embodiment, plastic fasteners are used that allow resilience and vibration dampening within frame  22  and simultaneously allow disassembly for warehousing, shipping and storage. 
     First axle assembly rod  34  and second axle assembly rod  36  extend from wheel  46  transversely through body member  18  to wheel  47 . First axle assembly rod  34  will preferably extend under first seat  24   a , while second axle assembly rod  36  extends under second seat  24   b . The first and second axle assembly rods  34 ,  36  are preferably straight, horizontal poles to simplify the design and keep manufacturing costs low, but there is not requirement that they be so, and they may in fact take on a wide variety of geometries and configurations, so long as they provide the transverse stability desired and, preferably, provide support for each chair  24 . In the most preferred embodiment, axle assembly rods  34 ,  36  will be approximately thirty-three inches long. 
     Tongue  14  extends longitudinally from frame  22  to couple carriage  12  to a towing land vehicle such as a bicycle. Tongue  14  may comprise one or more components or tubes firmly combined with fasteners, welds or other suitable means, or may be a single integral or homogenous component, or combinations thereof. Tongue  14  may include at least one hitching rod  38  and a hitch  40 . The material, size and cross-section of hitching rod  38  are not critical to the invention, so long as there is sufficient strength, durability, corrosion resistance, and adequate reach to couple with other land vehicles. In the most preferred embodiment, hitching rod  38  is manufactured from aluminum tubing approximately seventy-two inches in length and having a diameter of approximately one inch. A rearward end  38   a  of hitching rod  38  may be attached to a portion of second axle assembly rod  36  which extends beyond the outside of the body member  18  using any suitable attachment mechanism such as welding or mechanical fastening. A middle portion  38   b  of hitching rod  38  may be attached to a portion of first axle assembly rod  34  which extends beyond the outside of the body member  18  using any suitable attachment mechanism such as welding or mechanical fastening. In the preferred embodiment, plastic couplers are provided with fastening hardware to provide improved resilience and ready assembly and disassembly. 
     Hitch  40  may be attached to a forward portion  38   c  of hitching rod  38 . Hitch  40  may be any known hitch used for attaching a bicycle trailer to a bicycle. Hitch  40  is preferably attached to the forward portion of the hitching rod  38  using any suitable attachment mechanism such as welding or mechanical fastening. Hitch  40  may be removably attached to a bicycle at the frame adjacent the back wheel of the bicycle or at the bicycle seat post. 
     Preferred hitch  40 , illustrated in FIGS. 6-8, includes a bicycle frame fastening mechanism  60  for securing to a generally horizontal bicycle frame tube  61 . Most preferably, the point of attachment will be the chain stay of the bicycle. The chain stay is the part of a bicycle that runs parallel to the ground and that the rear tire attaches to. The chain stay is much closer to ground level than the seat post of a bicycle. Should the bicycle fall over, there is much less motion generated in the tongue  14  when attached to the chain stay. 
     Fastening mechanism  60  includes first and second plates  62 ,  64  selectively joined with fasteners  66 . Plate  64  may be joined to first and second receiving plates  68 ,  70 . Receiving plates  68 ,  70  may be separate plates as illustrated, or may alternatively be fabricated from a single piece such as a U-shaped plate. Receiving plates  68 ,  70  provide for a pin  72  that secures to flexible link  74 , which in turn is attached to hitching rod  38 . 
     Wheel set  15  includes a C-shaped rod  42 , an inside rod  44 , and at least one wheel  46 . The materials, shape and construction of C-shaped rod  42  and inside rod  44  are not critical to the invention, provided there is sufficient strength and corrosion resistance for the application. In the preferred embodiment, these parts are fabricated from hollow aluminum tubing of approximately one inch diameter. Preferably, rod  42  is C-shaped to have no sharp corners which might otherwise present hazards to persons nearby. The inside rod  44  may be a straight, horizontal pole. 
     The length of C-shaped rod  42  may vary, most preferably being long enough to allow a rider to step up onto rod  42  and will be long enough to not interfere with the wheel  46 . A larger diameter wheel  46  provides for a smoother ride and ready traversing of difficult terrain or pot-holes in the roadway or trail, and provides adequate ground clearance for carriage  12 . Consequently, C-shaped rod  42 , from end to end, may typically range in length from sixty inches to less than ten inches, but more preferably, the length of C-shaped rod  42 , from end to end, will range from forty inches to thirty inches, and will most preferably be approximately thirty-eight inches. 
     Wheel  46  includes an axle  54  slightly offset from parallel to the ground. A five degree angle of offset  37  is most preferred, which increases stability, eliminates shimmy, and enhances styling. Axle  54  may be removably attached to C-shaped rod  42  on one end, but in the preferred embodiment will be attached through plate  55 , extend through the center of wheel  46 , and removably attached to the inside plate  57  at the other end. The low center of gravity of trailer  10 , additionally combined with the five degree tilt at angle  37 , and the two-wheel support yields a very stable trailer  10  which is quite difficult to tip. Safety is therefore greatly enhanced in the present invention over the prior art of record. 
     Trailer  10  may optionally include a weather cover  56 . The cover  56  may be removably attached to carriage  12  to provide shelter to those inside carriage  12  during rain or other adverse weather conditions. Cover  56  will also provide shelter from sun or insects. The materials for cover  56  are not critical and may include plastic, vinyl, screen, netting or other suitable material, though cover  56  will preferably be waterproof to protect the contents of carriage  12  during adverse weather. Cover  56  is removably attached to front member  16 , tail member  20  and the sides of body member  18  using any suitable attachment mechanism such as snaps, hooks, or hooks and loops. In the preferred embodiment, cover  56  is removably attached to carriage  12  using snaps and hook and loop fasteners such as sold under the trademark Velcro. 
     In operation, tongue  14  will be attached to a bicycle through hitch  40 . One or two small children may be placed onto chairs  24   a  and  24   b  located within body member  18 . Cargo may be carried with the chairs  24  upright, or chairs  24  may be lowered as illustrated by dashed line in FIG.  5 . Consequently, it will be apparent that both cargo and children may be carried with an appropriate set-up. Cover  56  may optionally be attached. Then a bicycle rider may mount the bicycle and ride. The rider will be able to see children and cargo through shield  16 . Children or other animate cargo will be able to watch the scenic views through shield  16  as the rider is propelling the bicycle. 
     While the foregoing details what is felt to be the preferred embodiment of the invention and some suitable alternatives, no material limitations to the scope of the claimed invention are intended. Further, features and design alternatives that would be obvious to one of ordinary skill in the art are considered to be incorporated herein. The scope of the invention is set forth and particularly described in the claims hereinbelow: