U.S. patent number 3,785,677 [Application Number 05/214,713] was granted by the patent office on 1974-01-15 for boat support for trailers.
This patent grant is currently assigned to Calkins Manufacturing Company. Invention is credited to Oscar C. Calkins.
United States Patent |
3,785,677 |
Calkins |
January 15, 1974 |
BOAT SUPPORT FOR TRAILERS
Abstract
A boat support designed to accommodate changes in the load
distribution on a boat trailer. Self-balancing hull support roller
assemblies are combined on a supporting framework together with a
bow securing assembly. Limited movement is provided on the
framework between the bow securing assembly and the hull supporting
assembly to permit self-balancing of the hull supporting assembly
independently of the bow securing assembly. Such movement can be
provided by a limited pivotal connection between the trailer
framework and tongue of the trailer, by walking beam supports for
multiple hull supporting assemblies or by an arrangement which
allows limited elevational movement of the bow securing assembly
relative to the trailer framework.
Inventors: |
Calkins; Oscar C. (Spokane,
WA) |
Assignee: |
Calkins Manufacturing Company
(Spokane, WA)
|
Family
ID: |
22800146 |
Appl.
No.: |
05/214,713 |
Filed: |
January 3, 1972 |
Current U.S.
Class: |
280/414.1;
414/534 |
Current CPC
Class: |
B60P
3/1033 (20130101) |
Current International
Class: |
B60P
3/06 (20060101); B60P 3/10 (20060101); B60p
003/10 () |
Field of
Search: |
;280/414R
;214/505,506,84 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Friaglia; Leo
Attorney, Agent or Firm: Wells, St. John & Roberts
Claims
Having thus described my invention, I claim:
1. In a boat trailer:
a wheel-supported longitudinal framework adapted to be pulled by a
towing vehicle for road travel while carrying a boat in a loaded
position on the trailer;
bow securing means mounted at the forward end of the framework for
attachment to the bow of a boat in a loaded position on the trailer
during road travel to prevent longitudinal motion of the loaded
boat relative to the trailer;
self-balancing hull support means operably mounted at each side of
said framework about a common fulcrum, said hull support means
being free of rigid attachment to said bow securing means;
said self-balancing hull support means being composed of spaced
elements respectively engaged with the underside of a boat in a
loaded position on the trailer during road travel and serving as
the only elevational support for the boat, said elements being
paired on rigid frames pivotally mounted intermediate each pair of
elements so as to permit momentary reapportionment of load during
road travel between the paired elements independently of said bow
securing means.
2. A boat trailer as set out in claim 1 wherein said elements are
longitudinally paired and mounted on longitudinal frames pivoted
about transverse pivot axes located intermediate each pair of
elements for balancing of the load distribution between the paired
elements about the respective axis of the frame on which they are
mounted.
3. A boat trailer as set out in claim 1 wherein said elements are
all mounted to longitudinal walking beams extending longitudinally
along the framework and pivotally connected thereto about an axis
intermediate their ends constituting said common fulcrum.
4. A boat trailer as set out in claim 1 further comprising:
a lost motion connection between the bow securing means and said
framework for permitting free vertical movement of the bow support
means relative to the framework and relative to said hull support
means.
5. A boat trailer as set out in claim 1 wherein the movable support
means comprises a vertically slotted bracket on an upright mast
fixed to the framework;
an upright bracket adapted to be secured to the bow of a boat when
loaded on the trailer;
and a transverse pivotal shaft mounting the bow bracket to the
slotted bracket on the mast for limited vertical movement of the
bow bracket along said slot.
6. The apparatus as set out in claim 5 further comprising:
shock absorbing means operatively connected between the bow bracket
and mast for dampening vertical movement of the bow bracket
relative to the mast.
7. A boat trailer as set out in claim 1 wherein the wheel-supported
framework comprises a substantially rigid main frame carrying said
hull support means and elevationally supported by a transverse
wheel assembly;
and a longitudinal tongue extending forward from the main frame,
said tongue being pivotally connected to the main frame about a
transverse axis located forwardly of the wheel assembly.
8. A boat trailer as set out in claim 1 wherein the wheel-supported
framework comprises a substantially rigid main frame carrying said
hull support means and elevationally supported by a transverse
wheel assembly;
a longitudinal tongue extending forward from the main frame, said
tongue being pivotally connected to the frame about a transverse
axis located forwardly of the wheel assembly;
and stop means on said frame and tongue for limiting the angular
extent of pivotal movement between the tongue and main frame about
said axis.
9. In a boat trailer:
a wheel-supported longitudinal framework adapted to be pulled by a
towing vehicle for road travel while carrying a boat in a loaded
position on the trailer;
hull support means mounted at each side of said framework for
engagement with the underside of a boat in a loaded position on the
trailer during road travel;
an upright mast on the framework forward of said hull support
means;
and bow securing means freely vertically movably mounted to said
mast for attachment to the bow of a boat in a loaded position on
the trailer during road travel to prevent longitudinal motion of
the loaded boat relative to the trailer while permitting free
vertical movement of said bow securing means relative to the
mast.
10. A boat trailer as set out in claim 9 further comprising:
a lost motion connection operatively interposed between said bow
securing means and said mast permitting said free vertical movement
of said bow securing means relative to the mast.
11. A boat trailer as set out in claim 9 further comprising:
shock absorbing means operatively connected between the bow
securing means and said mast for dampening vertical movement of the
bow securing means relative to said mast.
Description
BACKGROUND OF THE INVENTION
This disclosure relates to an improvement in the type of boat
trailer illustrated by the disclosure in U.S. Pat. No. 3,512,667,
granted Apr. 21, 1969. The boat trailer includes self-centering or
self-balancing cradle assemblies for hull engagement. Each cradle
assembly is pivoted to the trailer framework about a transverse
axis intermediate front and rear rollers that engage and carry the
weight of a portion of the boat hull. In the patented disclosure,
weight of the boat is balanced between the rollers on each cradle
assembly, but two or more cradle assemblies are normally required
to support a boat of any substantial size, and heretofore rigid
frame connections have been utilized between these multiple cradle
assemblies.
In the use of such a trailer, the bow of the boat is normally fixed
to an upright mast at the tongue or front of the trailer, typically
through a locked winch and cable or rope. The transom of the boat
is normally tied down at the rear cradle assembly. The various hull
supports in the form of rollers, pads, bunks, etc., are located
along the framework to achieve desired weight distribution for the
boat hull while stationary on the trailer in a loaded condition.
They can be pre-adjusted for a particular boat. However, as the
trailer is used for road travel, minor momentary adjustment of the
loading arrangement is inevitable due to vertical movement of the
wheels as caused by road or surface variations. Upward or downward
movement of the wheels is transmitted to the framework, causing
momentary deflection of the framework and resulting load variations
on the various devices in contact with the boat hull. Assuming that
the hull itself is rigid, deflection of the trailer framework
causes some rollers to exert considerable increases in force on the
boat trailer surfaces, while other rollers might momentarily be
entirely free or disengaged from the boat surfaces. In practice,
this has resulted in wear at the exterior boat surfaces, a
condition particularly troublesome in the case of reinforced
plastic boat hulls, where the outer plastic material or gel coat is
often worn completely in the area of roller contact.
Another problem of load variation along a boat trailer arises from
the nature and use of a boat trailer, particularly when carrying a
pleasure boat. It frequently occurs that the boat user will utilize
the boat itself to transport spare boat motors, ice chests, camping
equipment and other various portable materials. The weight
variation and distribution along the trailer can vary considerably
from that for which the trailer is designed or pre-adjusted. This
often creates serious imbalances in the loading of the boat trailer
when at rest, and even further accentuates the problems of road
shocks during travel while so loaded.
The solution to these problems, as disclosed in detail in the
following description, is to provide essentially two point support
of the boat in the loaded or travel condition on the boat trailer
by a hull supporting assembly and a bow engaging assembly, and to
permit limited elevational variation between these assemblies
independently of one another. This requires a self-balancing hull
support assembly capable of engaging the hull along its horizontal
lenth. The hull support can be of the type shown in U.S. Pat. No.
3,512,667 or alternate hull supports which are self-balancing about
an intermediate fulcrum on the trailer framework so as to
automatically distribute the load between longitudinally spaced
rollers or other hull engaging members. With this improved
arrangement, momentary road shocks and variations in static load
are accommodated by the limited movement permitted between the two
assemblies on the boat trailer.
SUMMARY OF THE INVENTION
The invention relates to a boat trailer having a wheel-supported
framework, bow securing means mounted to the framework, hull
support means mounted to the framework and movable connecting means
on the framework between the hull support means and the bow
securing means for permitting automatic self-balancing of the hull
support means during road travel independently of the bow securing
means.
It is a first object of this invention to provide an improved boat
trailer configuration capable of absorbing and controlling the
application of varying static boat loading or momentary vertical
loading on the trailer framework due to road shocks or surface
conditions on which the trailer is traveling.
Another object of this invention is to provide several specific
devices for accommodating load variation in forms applicable to
most existing types of boat trailers.
Another object of this invention is to provide such an improvement
in a manner that does not necessarily add materially to the cost of
the boat trailer and which can be utilized at an added cost readily
justifiable by the resulting decrease in trailer damage or boat
hull damage during use of the trailer.
These and further objects will be evident from the following
disclosure, which sets out three specific forms of the basic
invention. These specific forms are presented by way of
illustration and other obvious adaptations of the concepts
disclosed herein will be readily observable by those skilled in the
art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side elevation view of a first form of the
invention;
FIG. 2 is a schematic side elevation view of a second form of the
invention;
FIG. 3 is a schematic side elevation view of a third form of the
invention;
FIG. 4 is a plan view showing the first form of the invention;
FIG. 5 is a side elevation view of the trailer shown in FIG. 4;
FIG. 6 is a plan view of the second form of the invention;
FIG. 7 is a side elevation view of the trailer shown in FIG. 6;
FIG. 8 is a plan view of the third form of the invention;
FIG. 9 is a side elevation view of the trailer shown in FIG. 8;
FIG. 10 is a perspective view showing the bow securing assembly of
FIGS. 8 and 9 at an enlarged scale; and
FIG. 11 is a top view of the bow securing assembly shown in FIG.
10, with the general outline of a boat bow illustrated in dashed
lines.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
GENERAL DESCRIPTION
FIGS. 1-3 schematically illustrate three arrangements by which one
can utilize the present improvement in the design of a boat
trailer. The following general description applies to these three
illustrative structures, which are shown in detail in the remaining
drawings. The reference numerals in this general description are
common to all schematic and detailed forms of the disclosure,
except in those instances which are specifically denoted with
respect to a specific embodiment.
The trailer comprises a main structural framework designated by the
numeral 10. Framework 10 includes a forward longitudinal tongue 11
and rear side members 12 which extend longitudinally along the boat
hull 26 at the respective sides thereof. Framework 10 is typically
supported by a transverse wheel assembly 13 which includes one or
more pairs of ground engaging wheels.
At the front of tongue 11 is a bow securing assembly 14. It
includes a winch 15 having a cable releasably attached to the bow
of the boat hull 26. The cable and winch 15, when secured, hold the
bow of the boat in a fixed position against a bow bracket 16
located at the upper end of a mast 17.
The hull supporting assemblies 18 are in the form of multiple pairs
of rollers, 22, 23, mounted at opposite longitudinal ends of
individual support frames 20, each frame 20 being pivotally
supported intermediate the rollers 22, 23 at pivot connections
shown at 24. Because of this intermediate pivotal support, the load
on the paired rollers 22, 23 is automatically balanced to attain a
working static condition. The pivotal support of the rearmost frame
20 is further utilized to assist in loading and unloading of the
boat hull 26 with respect to the trailer. The details of
construction and use of self-centering or self-balancing roller
supports of this general type are set out in U.S. Pat. No.
3,512,667, which is herein incorporated by reference.
To accommodate change in the loading applied to the trailer
framework 10 during road travel and to eliminate the usual
resulting excessive wear on the exterior surfaces of boat hull 26
caused by the rollers 22, 23 or other hull engaging devices,
provision is made herein for automatic self-balancing of the hull
engaging assembly 18 independently of the bow securing assembly
14.
As shown in FIG. 1, this is achieved by pyramiding the frames 20 on
transversely pivoted longitudinal frames 27 and ultimately
supporting them upon a main walking beam 28 at each side of the
boat trailer. Each walking beam 28 is pivoted to the side members
12 of framework 10 at pivot connection 30. Thus, automatic load
equalization or reapportionment is achieved between all of the
paired rollers 22, 23 along the full length of the boat hull 26,
and frame deflection or loading will be distributed through all of
these rollers, and not concentrated at any particular roller, nor
will any roller be momentarily freed from loading due to such
deflection.
In FIG. 2, the hull supporting assembly is not mounted to the side
members 12 at a single axis, but at two pivot connections 36 at
opposite sides of the wheel assembly 13. The tongue 11 is not
rigidly connected to the side members 12, but is pivoted to them
about a transverse pivot connection 33, which permits elevational
movement between the bow securing assembly 14 and the side members
12 that carry the hull supporting assembly 18. The extent of this
pivotal movement of tongue 11 is limited by upper and lower stops
34, 35 on the side members 12. This arrangement permits the hull
supporting assembly to reapportion the load during road travel by
pivotal movement about the fulcrum provided by the wheel assembly
13 and accommodates resulting movement between the hull supporting
assembly and the bow securing assembly without concentrating the
load at either the underside of the boat hull 26 or at its bow.
The solution shown in FIG. 3 can be utilized on any boat trailer,
although it also is preferably used in conjunction with
self-balancing hull supporting assemblies 18. In this
configuration, the tongue 11 and side members 12 form a rigid
framework 10, and provision is made at the upper end of mast 17 for
vertical movement of the bow bracket 16 with respect to mast 17 and
tongue 11. Again, this allows for load reapportionment during road
travel by the hull supports independently of the bow of the boat
hull.
In all three embodiments, there is a basic common support concept
insuring reapportionment or balancing of force application along
all of the rollers 22, 23 at any given time during road travel.
This is accomplished by mounting the balanced frames 20 or other
suitable hull engaging devices about a single transverse fulcrum
with some of the rollers forward of the fulcrum and others rearward
thereof to enable the rollers to balance one another automatically
and thereby reapportion the weight of the boat between them.
Secondly, the member pivoted or connected to the fulcrum is free of
rigid attachment to the bow bracket 16, which is fixed with respect
to the front end of the boat hull. The bow bracket 16 thus serves
to fix the longitudinal position of the boat hull on the trailer,
but does not interfere with the balanced support of the boat hull
itself.
In FIG. 1, the common fulcrum is at pivot connections 30, and all
of the rollers 22, 23 are mounted on pivotal frames so as to
balance one another at both sides of the main fulcrum. The pivot
connections 30 and walking beams 28 supported thereby eliminate
rigid connection between the bow brackets 16 and the rollers 22,
23. Thus, rollers 22, 23 can readjust their weight distribution
without being hampered by the reaction of any rigid frame
connection to the front of the boat hull.
In FIG. 2, the common fulcrum is provided across the wheel assembly
13. Again, rollers 22, 23 are balanced on the framework at opposite
sides of the fulcrum and are supported by pivotal frame members in
such fashion as to automatically balance each pair of rollers 22,
23, as well as to balance one another at opposite longitudinal
sides of the fulcrum provided by wheel assembly 13. In this
instance, the bow bracket 16 is freed by the pivot connection 33
from rigid attachment to the longitudinal support for the
rollers.
In FIG. 3, the rollers 22, 23 are carried on self-balancing
individual frames, which in turn are pivotally balanced at opposite
longitudinal sides of wheel assembly 13, which acts as the main
fulcrum for the framework 10. In FIG. 3, the hull support
independent suspension for the main roller support (framework 10)
is provided by the free vertical movement afforded to bow bracket
16 relative to mast 17.
FIRST EMBODIMENT OF THE INVENTION
FIGS. 4 and 5 show in detail the structure of the first embodiment
of the invention shown schematically in FIG. 1. The transverse
wheel assembly 13 supports the longitudinal side members 12 of the
main framework 10, which converge forwardly and are rigidly secured
to a longitudinal center tongue 11. The bow securing assembly is
rigidly located near the forward end of tongue 11, which is
provided with a conventional hitch for attachment to a towing
vehicle. A winch 15 has a cable adapted to be secured to an eye
(not shown) at the front of a boat. The eye is drawn through the
center of a V-shaped upright bow bracket 16 rigidly mounted to mast
17. The bracket 16 cradles the pointed bow of the boat and prevents
the boat from moving longitudinally, while maintaining it in a
centered condition at the front end of the boat.
In the drawings there is shown a center protective roller 25
located at the convergence of the side members 12 immediately
rearward of the tongue 11. This roller 25 might be casually
mistaken for a conventional keel roller, but it does not serve the
normal function of a keel roller. A conventional "keel roller"
along a boat trailer is used as a support for a loaded boat. The
purpose of roller 25 is to prevent the forward end of the boat from
being damaged by contact with the frame members during loading of
the boat onto the trailer. It acts as a roller guide to assist in
lifting the front end of the boat over the tongue 11. When the boat
hull is loaded onto the trailer, the hull is elevationally above
roller 25 and not further supported by roller 25 in any way. The
use of keel rollers or other fixed supports along the trailer frame
is in contradiction to the basic purpose of this disclosure, namely
the complete balancing of all vertical load support members about a
common fulcrum on the framework 10.
The illustrated trailer in FIGS. 4 and 5 is provided with three
cradle frames 20, each having balanced forward rollers 22 at the
center of the frame 20 and side rollers 23 at the open rear ends of
each frame 20. The side rollers 23 are mounted to the frames 20 for
pivotal movement about the longitudinal center axis of the open
frame legs to permit the rollers to conform to the side inclined
configuration of a boat hull. Each cradle frame 20 has its rollers
22, 23 movably balanced about a free transverse pivot axis by means
of a cradle frame pivot connection 24. In addition, where two or
more cradle frames 20 are used in conjunction with one another at
one side of the main framework fulcrum, it is necessary to provide
intermediate longitudinal frames 27 which interconnect the pivot
connections 24 and which in turn are pivoted about common
transverse axes by means of an intermediate pivot connection
36.
In this embodiment, which utilizes a substantially rigid framework
10, the rollers 22, 23 are ultimately balanced about a transverse
fulcrum provided across walking beams 28 which support the entire
roller assembly. The longitudinal walking beams 28 support the rear
cradle frame by its pivot connection 24. They support the two front
cradle frames 20 by the pivot connections 36 of the interposed
frames 27. Walking beams 28 in turn are pivotally mounted to
framework 10 by coaxial transverse pivot connections 30 between the
walking beams 28 and the respective side members 12.
In this form of the invention, all of the rollers 22, 23 are
balanced about the fulcrum of the walking beams 28, so that any
load forces transmitted from the framework 10 to walking beam 28
will be automatically balanced between the freely pivoted rollers
22, 23 and such loads will not be concentrated at any particular
roller area. The expected deflection of framework 10 will not cause
undue stress on the boat hull due to the rigid connection provided
at bow bracket 16, since the framework is isolated from rigid
connection to the hull supporting assembly 18 by the common fulcrum
provided at the pivot connection 30.
SECOND EMBODIMENT OF THE INVENTION
The second embodiment of this invention is shown in detail in FIGS.
6 and 7 and is schematically illustrated in FIG. 2. In this form,
the framework 10 includes side members 12 that extend
longitudinally over the wheel assembly 13. Tongue 11 further
includes longitudinal extensions 37 which overlap the forward ends
of side members 12 and which are pivotally connected thereto at 33.
The forward ends of side members 12 have protruding upper and lower
stops 34, 35 which define the respective limits of pivotal movement
of the tongue 11 relative to side members 12.
The bow securing assembly 14 is identical to that shown in FIGS. 4
and 5. The rollers 22, 23 are also similarly mounted to those in
FIGS. 4 and 5, but the rear cradle frame 20 and the intermediate
frame 27 are pivotally connected at 36 to the side members 12,
rather than to longitudinal walking beams. In this instance, the
side members 12 serve a function similar to that of the walking
beam illustrated in FIGS. 4 and 5. Vertical deflection along the
side members 12 due to road shocks transmitted through wheel
assembly 13 or variations in the trailer load will be automatically
balanced and compensated among the freely pivoted rollers 22, 23 at
each longitudinal side of the fulcrum provided in the framework by
the wheel assembly 13. This ability to redistribute load along the
framework is possible due to the freedom of movement afforded
between tongue 11 and side members 12 through the pivot connection
33.
With respect to FIGS. 6 and 7, this pivoted tongue arrangement is
not to be confused with prior pivoted tongue devices which were
designed to facilitate loading or unloading of boats. As an example
of such prior devices, attention is called to U.S. Pat. No.
3,057,493, granted Oct. 9, 1962. The purpose of these prior pivot
tongue connections was to permit the rear end of the rigid frame to
be lowered for launching or retrieval of a boat in the water.
During road transport usage, the tongue and frame are rigidly
interlocked with no provision for relative free movement between
the bow support and the rollers or other members engaging the
underside of the boat. The pivot connection that exists between the
tongue and longitudinal side members in FIGS. 6 and 7 does not
provide sufficient freedom for pivoting the rear of the frame to be
substantially useful in launching or retrieving the boat. As noted
above, the lowering of the frame is unnecessary when the
illustrated type of roller assembly is used, since the rearmost
rollers 23 on the trailer are free to be lowered elevationally
about the pivot connection 24 of the cradle frame 20 supporting
them.
THIRD EMBODIMENT OF THE INVENTION
The third embodiment of the invention is shown in FIGS. 8-11. The
main framework 10 of the trailer is substantially that previously
discussed with respect to FIGS. 4 and 5. The illustration shows
only a single cradle frame 20 forward and rearward of the wheel
assembly 13, with their pivot connections 24 being directly
connected to the side members 12. It is to be understood that in
all of the embodiments, greater numbers of cradle frames 20 can be
pyramided at either side of the main fulcrum of the framework 10,
which in FIGS. 8 and 9 is provided between the connection of the
wheel assembly 13 and the side members 12.
Details of the third embodiment are best seen in FIGS. 10 and 11.
In these Figures, the winch cable 38 is shown provided with an
outer hook 39 for attachment to the bow of a boat through the
center of the bow bracket 16. This operative position of the cable
38 and hook 39 is shown in dashed lines in FIG. 11. When hook 39 is
attached to the bow of a boat and the bow is pulled forwardly into
engagement with bracket 16 with tension on cable 38, the boat is
rigidly fixed relative to the bracket 16. However, in this
arrangement, the bracket 16 is vertically movable along upright
slots 40 formed through rearwardly facing ears 41 at the upper end
of mast 17. A transverse pivot shaft 42 on the bow bracket 16 is
received through slots 40. Shaft 42 permits pivotal motion of the
bow bracket 16 to conform to the bow configuration and guides the
bracket 16 vertically along the length of slot 40.
While the brackets 16 can be freely supported by the pivot shaft 42
alone, it is desirable that movement of the bow bracket 16 be
dampened. This is preferably accomplished by interconnection of a
conventional hydraulic shock absorber assembly 43 between the bow
bracket 16 and the mast 17. The apparatus is preferably adjusted so
as to normally locate the pivot shaft 42 at the elevational center
of slot 40, whereby the bow bracket 16 is then free to move
slightly upwardly or downwardly in response to subsequent load
variation along the trailer framework 10. As discussed above, the
trailer rollers 22, 23 are balanced at the longitudinal sides of
the fulcrum provided by the wheel assembly 13, and are free to
compensate among themselves to accommodate reapportion the changing
load of the boat hull applied to rollers 22, 23 to road forces
transmitted through the side members 12 without hindrance of a
rigid framework connection to the bow of the boat. The slots 40
provide a "lost motion connection" freeing the bow of the rigid
boat hull from the deflection of the longitudinal trailer framework
members.
CONCLUSION
The three illustrative embodiments of this invention can be
combined with one another if this is desired to further insure
adequate freedom along framework 10 to accommodate road shocks. The
amount of free movement required for such compensation purposes is
dictated somewhat by the allowable deflection along the trailer
frame members. It is to be understood that other types of balanced
roller or hull engaging devices may be substituted in place of the
U-shaped cradles illustrated in these drawings and that many minor
modifications might be made with respect to the basic arrangement
of components described herein. Because of the many possible
variations, only the following claims are intended to limit and
define the scope of the invention set out in this disclosure.
* * * * *