Note: Descriptions are shown in the official language in which they were submitted.
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IMI'ROVI~D TIRAVEL l`RAILER
- l'EC~INICAL F IELD
l`he present inventioll rela~es to al1 improved ~ravel trailer an~l a metholl
vf constrllctillg the improve~l travel trailer. More particularly, the present
invention relates to a travel trailer with a subfloor space beneath the living area
which allows major colIlpollents suclI as air conditioners, heaters, ulility lines,
an~l wa~er, propane an~ sewage tanks, to be carrie(l beneath the main living area
of the trailer, while at the same time being enclosed an(l accessible from the
sides of tlle travel trailer.
BA~KGROUND OF THE INVENTION
The general ~lesign and conslruction of residential trailers and
recreational travel lrailers 5Ias been pracliced for decades and is well-known.
ResisJelItial trailers or mobile holIles are typically designe(l wilh living a~
storage areas sitting on frames which have four or more parallel, load-bearing,
longitudinal beams with a plurality of transverse, load-bearing members arraye(lalong the length of the longitu(linal beams. Examples of ~IIese typical ~railer
frame (3esigns are shown in U.S. Patent No 4,0X4,834, issue(l to Becker and U.S.Patent No. 4,863,1~9, issued to Linsday. Tlie frames taught in Becker and
Lindsay have longitucJinal beams on the outer silles of the frames forming a
2S perimeter wllicl1 approximates tlle width an(l lengtll of the trailer.
Similarly, recreational travel trailers largely have adopted mobile home
desi~ns of tlle type discussed above with living and storage areas sitting on a
frame, although travel trailers typically use frarlIes with only lwo outer
lon~itudilIal beams. I he use of a mol)ile hollIe frallle (lesign for lravel trailers
presents limitations and problems for the manufacturers of travel trailers due to
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differences between the two types of trailers in terms of their purposes and themanner in which they are used.
As the name implies, mobile homes are relatively large with a size of 70
feet by 14 feet or even larger not unllsual. Mobile homes typically are
5 transported by professional driveirs using large cornmercial trucks, and frequently
are only moved once or twice during their existence. Manufacturers of mobile
homes have some flexibility in the possible configurations or layouts for the
living and s~orage areas of mobile homes simply due to their size. Also, since
mobile homes frequently are place(l in a permanent location, additional storage
10 areas outside the mobile home can be used. As a result of the above factors,
structural strength is of premier importance, with weight, efficiency, and location
of major components and utililies being mucb less important.
Travel trailers, on tlle other hand, are considerably smaller than mobile
homes, ahnost always are towed by their owners with a passenger car or light
15 truck, and typically are moved often and for great distances. Given these
circumstances, owners of travel trailers must store most or all of the items they
will require in the travel trailer while minimizing the intrusion into the limited
living area. As a result, manufachlrers of travel trailers are concerned with
structllral integrity of their units, but at the same time, they also must be very
20 concerned with making travel trailers as lightweight as possible without
sacrificing strength. The distribution of the weight as well as the amount of the
weight must also be considered since the towability of a frequently towed traveltrailer are much more important than that of the seldom moved mobile homei.
Other important considerations in the design and construction of travel
2~ trailers are the efficient utilization of the limited space in the living and storage
areas, and accessibility of major components which may require replenishment
such as wa~er, fuel, and sewage tanks, or repair such as air conditioners, waterheaters, furnaces, and utility lines. These factors have become increasingly
important over the years as travel trailers have become more expensive and
30 more sophisticated to meet the requirements of a more demanding purchasing
public. This is especially true of that growing portion of travel trailer ownerswho spend most or all of their time in their travel trailers. The utilization of the
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fifth-wheeler or goose-neck design which allows an increase in the length of thetrailer without a corresponding length increase of the tow vehicle-travel trailer
combination is one attempt to e7~pan(1 the living area efficiently.
The mobile home frame design with the outer, longitudinai beams forces
5 travel trailer manufacturers to make unsatisfactory choices. Components such
as air conditioning units and heating units can be placed: 1) on top of the
trailer, raising the center of mass and requiring a greater load bearing capacity
from the trailer roof; 2) in the living area, using already limi~ed space and
limiting the different layouts possible; or 3) underneath the travel trailer, where
10 access is difficult and the componellt is exposed to the elements and any objects
in the road. Similar ullsatisfactory choices are true for utility lines, electric,
water, and sewer, and the fluid tanks used in travel trailers.
Typically, travel trailer manufacturers llave adopted a combination of
choices wllich restrict the configurations and space available in the living area.
15 Examples are roof-mounted air conditioners, heaters installed in the livin~ area,
electrical and water lines routed through cabinets, and exposed tanks and lines
un(lerneath the travel trailer. T}le result is a travel trailer with vital components
exposed to wea~her and hazards of the road, substantial restrictions on the sizeand configurations available for people and storage, and difficulties in routine20 service and repair due to limited access to the necessary components both inside
and outside the travel trailer. The manufacture and assembly of travel trailers
like those described above is also more difficult.
As illustrated by the above discussion, there are a number of desirable
features for a recreational travel trailer. It wollld be desiral)le to have a travel
2~ trailer which maximized the number of layouts available for the living area, and
filrther maximized the living and storage space available with a minimal increase
in the overall size of the travel trailer. It also would be desirable to remove
major components from the living and storage areas of the travel trailer, and
from its top. Further, it would be desirable to have access to major components
30 for service and repair from the outside of the travel trailer. Additionally, it
would be desirable for major components located outside the travel trailer living
area to be enclosed. It would be desirable also any improved design for a more
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efficient travel trailer to adaptable to either a conventional or fifth-wheel
configuratis)n.
While the discussion herein relates to recreational travel trailers, it is not
intended that the invention be limited to this situation. It will be obvious from
the description that follows that the present invention will useful in other
applications with problems common to those describe(l herein.
SU !vlMARY OF THE INVE~TION
It is the object of the present invention to provide a travel trailer which
t0 maximizes the different living area configurations available.
It is the filrther ol)ject of the present invention to provide a travel trailer
which maximizes the space available for the livin~ and stora~e areas while
minimizing any increase in the overall size of the travel trailer.
It is also the object of the present invention to provide a travel trailer in
lS which the major components can be simpler and less expensive to operate,
maintain and repair.
~t is yet another object of the present invention to provide a travel trailer
in which most of the major components are located outside the living and
storage area of the travel trailer and are enclosed.
The present invention achieves these and other objectives which will
become apparent from the description that follows, by providing a travel trailerwith a subfloor space that extends substalltially beneath the entire travel trailer
living area. The subfloor space has a subfloor created by a rectangular, planar
piece of substantially rigid material whicll has a width and length substantially
a5 eqllal to the wklth and length of the travel trailer itself. The subfloor is the
bottom of the subfloor space and is attached to the hottom of the travel trailerframe. A second rectangular, planar piece of substantially rigid material with
a width and length substantially equal to the width and length of the travel
trailer forms the top of the subfloor space and can also function as the floor of
the travel trailer living area. The floor piece rests on ~op and is attached to the
travel trailer frame. Thus, the travel trailer frame is substantially enclosed by
the subfloor space.
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In this embo~iment, componelIts which do not have to be inside the
travel trailer living area are located within the subfloor space. The propane
tanks, furnace, water tank, water heater, and batteries are examples of
components located in the subfloor space. In addition, items such as electric
S and water lines and heat ducting are routed through the subfloor space and
extend into the living area only where they are required to make connections foruse occupants. Similarly, components such as air conditioners may be move(l
from roof locations to the subfloor space. Items such as circuit breakers and
other cornponents of the electrical system, and water pump and fill valve for the
10 fresb water system are located in the subfloor space also.
The placement of the above components in the subfloor space
dramatically increases both space and possible layouts available for the travel
trailer living and storage areas. Also, the removal of these components from thetravel trailer living area insulates the living area from the noise and heat of their
15 operation. Service and repair of the components located in the subfloor spacefrom outside of the travel trailer is easier and more convenient. Further, the
addition of the subfloor for the subfloor space creates a thermal insulating layer
which substantially redllces heat loss from the living area.
In an alternative preferred embodiment, the travel trailer creates a
20 subfloor space as described in the above preferred embodiment using a frame
with two main rails which extend substantially the length of the travel trailer and
are substantially parallel to one another. The main rails in this embodiment arecolmected by at least two cross members. The main rails are located
substantially inward from the sides of the travel trailer whicll allows many of the
25 components to be located in the subfloor space and outside the main rails, thus
maximizing access for service and repair.
In another alternative preferred embodiment, the subfloor space and
narrow frame described in the above embodiments are used on a trailer with a
goose-neck configuration. In this embodiment, there is no subfloor space or
30 subfloor under the elevated portion of the travel trailer.
In an additional preferred embodiment, an ~xle subassembly is provided
which in conjunction with the narrow ~rame described above. The axle
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subassembly serves two fullctions. I-irst it provides an additional frame memberwhich increases the rigidity of the overall frame by attaching to the main rails.
At the same time, tlle axle subassembly provides stability for the trailer axlespresent in the frame designs using outer longitudinal rails.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a partial, front isometric view of a preferred embodiment
constructed in accordance with the present invention.
Fig. 2 is a partial, front isometric view of a preferred embodiment
10 constructed in accordance with the present invention.
Fig. 3 is a partial, exploded front isometric view of a preferred
embo(liment constructed in accordance with the present invention.
Fig. 4 is a partial, exploded front isometric view of a preferred
embodiment constructed in accordance with the present invention.
Fig. 5 is a side elevation view of a preferred embodiment constructed in
accordance with the present invention.
Fig. 6 is another side elevation view of a preferred embodiment
constructed in accordance with the present invention.
Fig. 7 is a partial, cross-sectional view of a preferred embodiment
20 constructed in accordance with the present invention taken along line 7-7 in
Fig.'s 5 and 6.
Fig. 8 is a partial, front isometric view of an alternative preferred
embodiment constructed in accordance with the present invention.
Fig. 9 is a partial, front isometric view of an alternative preferred
~5 embodiment constructed in accordance with the present invention.
Fig~ 10 is a side elevation view of an alternative preferred embodiment
constructed in accordance with tlle present invention.
Fig. 11 is another side elevation view of an alterna~ive preferred
embodiment constructed in accordance with the present invention.
- DETAILED DESCRIPTION OF PREI~ERIREI) EMBODIMENTS
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With reference to FIC~.'s 1 and 2, a travel trailer frame 10 for the goose
neck configuratiorl with inwardly set main rails 12 is shown. The main rails
extend isubstantially the length of the travel trailer main frame or lower frame13. l he main rails also are substantially parallel tv one another. Proximate the
5 rear ends 14 of the lower frame main rails is a rear cross member 16 which
connects tl1e main rails together. Located at the front 18 of the travel trailerlower frame is a front cross member ~0 which is another connection between the
main rails.
The elevated or goose-neck frame 21 of the travel trailer is attached to
10 the front of the travel trailer mah1 frame by a pair of vertical frame members
22. The vertical frame members ex~end upwardly from either end of the front
cross member to connect to the trailer elevated frame at 90 degree angles. The
attachment betwecn the vertical frame members and the trailer elevated frame
can be strengthened by upper angled braces 23. Similarly, lower angled braces
15 24 can be used between the mah1 rails an-l the front cross member.
The axle subassembly 25 attaches the axles 26 to the main rails and also
acts as an additional cross member which connects the main rails together, as
shown in FIG. 2 and in greater detail in FIG. 3. The axle sul)assembly has two
a~le support beams 28 to which the axles are attached with axle hangers 30.
20 The axle support beams are located outward from and substantially parallel tothe main rails. Attached to the axle support beams by a plurality of secondary
braces 32 are at least two load transfer beams 34 that are located immediately
forward and rearward of the axles. The load transfer beams are substantially
perpendicular to the main rails and the axle support beams. They also are no
25 longer than the trailer is wide. The entire axle subassembly is a~tached to the
frame`by a plurality of primary braces 36. An axle subassembly could be
provided for each individual axle.
The resulting axle subassembly is a rigid frame member that strengthens
tl-e frame. At the same time, the axle subassembly witll its outwardly positione(l
30 axle support heams, provides the same stabilily folln(l in trailer frames using
outer longitudinal main rails while allowing the use of the inwardly mounted
main rails and their inherent advantages.
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The lateral location of the main rails can vary considerably depen~ling
upon the size of a particular travel trailer and the needs of a particular
manufacturer. A great deal success has been achieve~ with the main beams
located so that they approximately trisect the overall width of the travel traiier
S with each one being located inward a distance equal to about one-third of the
overall width of the trailer. The materials and methods of construction
used to manufacture the travel trailer frame for this embodiment are
substantially the same as those used Wit}l conventional travel trailer frames and
are well known by those skilled in the art. For example, connections between
10 frame members can be made by welding, bolting, or some combination of both.
Referring to FIG. 4, a subfloor 38 forms the bottom of the subfloor space
40 and is attached to the bottom o~ main rails, the front cross member, and the
axle support beams. The main floor 42 rests atop and is attached to the rear
cross member and the load support beams as shown in FIG.'s 4 and 7 and forms
15 the top of the subfloor space. In this embodiment whicll is a goose-neck (~esign,
the top of the subfloor space is defined further by the bath floor 44 which is at
an intermediate height between the travel trailer main *ame and the elevated
frame. Thus, the subfloor space extends substantially the length an(l wi~3th of
the lower frame. As shown in Fi8. 7, the main floor section extends over the
20 wheels 46. This fact, together with the elimination of shock absorbers by using
axles with rubber ride torsion suspension 48, does away with any intrlJsion intoliving or storage areas by the wheels or suspension.
The height of the subfloor space should be tall enough to allow for wheel
motion and to provide adequate area fi)r the placement of compvnellts. Beyond
2S these factors, the subfloor space height can vary according to the needs of the
mamlfacturer, but gOod results have been obtained with heights up to
approximately 15 inches. If the subfloor space height exceeds this amount by
much, the center of mass and overall height of the travel trailer is raised to the
point that the trailer towability is adversely effected. The increase in height of
30 a travel trailer constructed in accors3ance with the present invention is
compensated at least in part by the relocation of components to the subfloor
space.
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A~ illustrate~3 in FIG.'s 4-6, this embodiment allows fhe travel trailer
manufacturer to place components in the subfloor space that do not have to be
in the living area. ~any of these components can be placed in separate
compartments. The propane tanks 50 have ~een placed in a compartment 52
S in the subfloor at one side of the trailer. The batteries 54 also are in the
subfloor space in their own compartment 56 which opens to a one side of the
travel trailer. The compartments in the subfloor space can be enclosed in a
variety of ways. FIG.'s S and 6 show doors 52a and 56a which are used to
enclose the respective compartments.
As with the above components, the furnace 5~ is located in the subfloor
space and is accessible at a side of the travel trailer. The warm air is returned
to the furnace through the subfloor space which heats the entire subfloor space.This heating helps to keep the components located in the subfloor space warm
and also the insulating effect on the living area by the subfloor space. The
15 heating ducts 60 and 60a for the furnace are routed underneath the main floortoo. This eliminates the need for placing the furnace in the living area or
routing heating ducts through cabinets and closets. The circuit breaker box
62 for both the 110 volt and 12 volt electrical system carl be reached easily atthe side of the travel trailer, as can the cord storage box 64 in which the
20 electrical cord for outside electricity is stored. In this embodiment, the wiring
6~ is routed through the subfloor space instead of the cabinets and closets in the
living area. In the subfloor space, the wiring can be attached directly to the
main rails which allows the wiring to be protected and reduces the need for any
sort of protective covers. The only time the electrical wiring is routed into the
25 living area is to make a specific connection for a light fLxture, switch, or o~her
electrical outlet. Further, with the routing configurations discussed above, theonly electrical connections or splices in the wiring can be located either in the
living area at the device requiring the electrical outlet or outside the trailer at
the circuit breaker box. Thus, the need for splices or connections in electrical30 wiring in the subfloor space under the travel trailer living area can be
eliminated. This vastly simplifies maintenance procedures for travel trailers
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since the connections or splices are the most likely area of the electrical system
to need repair.
Similar rGuting configurations for water lines and other facilities, which
eliminates connection or junctions in hard-to-reach areas, can be used. ~or
example, the fresh water system is installed in the same manner with the active
components, the pump 68, the fill valve 70, and the distribution manifolds 72,
located and accessible in the subfloor space. As with other systems, water pipes74 are routed through the subfloor space, emerging in the living area only as
needed. Tjunctions and other plumbing connections are located proximate the
lO water outlets whenever possible to reduce need for repairs at relatively
inaccessible locations. A number of advantages are realized when a travel
trailer is constructed in accordance with this embodiment. First, physical
intrusions into the limited living area by needed components virtually are
eliminated. This greatly recluces restrictions on the possible layouts of the living
15 area. In fact, even the layout of the relocated components in the sub~loor space
can be changed as desired by the manufacturer. At the same time, the
relocation of components to the subfloor space increases the storage area
available which is important for persons who must carry all or most of their
necessities with them.
Greater ~lexibility with the location and design of other components also
is available. For ex~mple, waste water storage tank capacity can be increased
and the tanks 76 themselves can be designed for more efficient operatiorl. The
waste water tanks are designed to extend substantially the width of the t~avel
trailer. This allows vent pipes to be located immediately next to walls. ~Iso,
25 the long narrow tanl~ is easy to remove through a door in the side of the travel
trailer~ The size of water tank 78 can also bs increased, as can the el~iciency of
its operation as part of the travel trailer.
The relocated components and appliances which can be serviced and
repaired from the outside the trailer simplify the operation and maintenance of
30 a travel trailer. Another advantage is the increased insulation of the living area.
With the introduction of the subfloor and the enclosed subfloor space, the
thermal insulation of the living area is increased. Not only is thermal loss
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reduced, but also heat resulting from the operation of components, such as the
water heater 79, is kept out of the living area during summer months. In
addition to thermal insulation, audio insulation is increased, because the noisefrom such things as the furnace and the water pump have been placed beneath
5 the main floor in compartments opening to the outside of the travel trailer.
Available storage space is increased so much that virtually every
component, even non-critical components such as the steps 80 are enclosed
within the subfloor space. The enclosing of these components results in a trailer
bottom 82 that smooth except for the drainage device 84 for the waste water
10 tanks, as illustrated in FIG. 5. The travel trailer is more aerodynarnic and,therefore, more efficient to operate. At the same time, these components also
are protected from the weather, and wear and tear that would occur when
exposed to the environment of the open road. Also, large unobstructed storage
spaces, such as storage compartment 86, can be provided wi~h the present
15 invention. As with the other compartments in the subfloor space, the storage
compartment can be enclosed by door 86.
In another preferred embodiment of the present invention, the
conventional configuration travel trailer is shown with the enclosed subfloor
space 90 in FIG.'s 8 and 9. This embodiment also uses a frame 92 with two main
20 rails 94 located inward from the sides of the travel trailer and an axle
subassembly 96. As above, the axle subassembly has axle support beams 97
connected to load transfer beams 98 by secondary braces 100 while the entire
subassembly is attached to the mail rails by primary braces 102. Ihere are also
a front cross member 104 and a rear cross member 106.
~5 The discussion of the above embodiment applies equally to this
embodiment. Specifically, as illustrated in FIG.'s 10 and 11, major components,
such as propane tanks 110, waste water tanks 116, water heater 118, and
batteries 124, can be stored in the subfloor space 108. Similarly, utility lines9
such as the water distribution manifold 120, and other objects like the steps 112
30 can be stored in the subfloor space. The result for the conventional travel
trailer is the same as for the to the goose-neck travel trailer with the attendant
benefits of increased space, including more enclosed storage compartments 114,
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better design flexibilil;y, etc. In this embodiment, the subfloor space extends
substantially over the entire wid~h and length of the travel trailer itself, since
there is no elevated frame port;on. Also, since the components are located in
the subfloor space, they are protected from the elements and the travel trailer
bottom 121 is smooth except for the drainage device 122.
Regardless of the configuration used, the benefits of the present invention
are undirninished. The travel trailer built using the present invention has moreroom, is more efficient to tow and to maintain, has a living area with better
thermal and audio insulation, and can be designed in a greater variety of livingarea configurations than the corresponding travel trailer with a conventional
frame.
INDUSTRlAL APPLICABILITY
The present invention is applicable in any situation where it is desirable
to maYimize areas available for living and storage in a trailer or other enclosed
space where the overall size is limited. The present invention also is applicable
where flexibility in the layout of living and storage areas of a trailer or other
enclosed space is desirable.
In compliance with the statute, the invention has been described in
~0 language more or less specific as to structural features, it is understood,
however, that the invention is not limi~ed to the specific features shown, sincethe means and construction herein disclosed comprise preferred forms of putting
the invention to effect. The invention, therefore, is claimed in any of its forms
or modifications within the legitimate and valid scope of the claims that follow.
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