US3039629A - Resilient cradle for boat trailers - Google Patents

Description

2 Sheets-Sheet 2 N. E. COLE June 19, 1962 RESILIENT CRADLE FOR BOAT TRAILERS Filed July 2, 1959 E a m m E m w QN S L E N w Y B @N E J JWMHHHHHHHHHHHH "X I I I I I I I QN ON 0N PN ATTORNEY United States Patent C) 3,039,629 RESILIENT CRADLE FQR BOAT TRAJLERS Nelson E. Cole, Reading, Pa., assignor to Dana Corporation, Toledo, Ohio, a corporation of Virginia Filed July 2, 1959, Ser. No. 824,589 6 Claims. ((11. 214-84} This invention relates to improvements in boat trailers in general and is particularly directed to improvements in boat trailers equipped with cradles which are capable of providing firm, resilient supports for a boat hull, and further which are readily deformable under load so as to conform with a variety of different shaped hulls.

A primary object of this invention is to provide a boat trailer with a plurality of cradles. The cradles are composed of a mounting shaft and a pair of relatively large fluid pressure filled bags which are freely rotatable on the mounting shafts. These cradles are supported by the frame of a conventional boat trailer and are used as a loading, unloading and transporting medium of boats and further will conform to different sizes and shapes of boat hulls without adjustment thereof.

A further object of the invention is to provide a cradle adapted to support a boat hull thereon with the forces on the cradle caused by the weight of the boat hull being mainly tensile in nature rather than compressive whereby the cradle is not compacted into a harder mass but remains substantially as resilient under load as it was prior to the application of the load.

Further objects and advantages will become apparent upon reading the following specification together with the accompanying drawings which form a part hereof.

In the drawings:

FIG. 1 is a perspective view of a boat trailer equipped with the resilient cradles of this invention.

FIG. 2 is a side elevation view of the resilient cradle partly in section.

The improved cradle of this invention embodies a struc tural form which permits it to support a boat hull resiliently over a broad area so that when the contacting surfaces of the cradle are placed under load, the forces acting thereon are more tensile in nature rather than purely compressive as has heretofore been the custom. These resilient fluid pressure filled bags when subjected to the load of a boat hull deform under the load so as to conform to different sizes and shapes of boat hulls.

Prior art boat trailers have been made from a plurality of supporting surfaces in the form of rollers which are usually longitudinally aligned and laterally spaced so as to provide points of support fora boat hull placed thereon. These rollers are particularly advantageous for loading, unloading and carrying a boat. The rollers of these prior art boat trailers have utilized resilient material for the actual contacting areas thereof because it is necessary that the rollers be yieldable to prevent damage to the boat hull being transported thereon. The resilient material of these rollers has customarily been rubber or rubberlike material but the construction has been of a type wherein the resistance to deformation under load progressively increases as the load is applied with the result that the rollers become compacted and hard due to the compressive forces thereon. Various forms of boat cradles exist in the prior art such as those made from a resilient material sleeved over a shaft. When cradles such as these are used to support a boat hull, however, they are loaded in compression with the result that the resilient material of the rolls therein is compacted, increasing the resistance to deformation and this increased deformation thereof causes a relatively hard support area which results in a high number of damaged boat hulls, especially those hulls made of plastic material. This results in either the boat hulls being reworked or scrapped. A further assaszs Patented June 19, 1962 objection to boat trailers of this type is that the support areas are relatively small, resulting in substantially a line contact of high unit pressure loading.

As shown in FIG. 1, a boat trailer, indicated as a whole by the reference numeral 10, is equipped with three cradle assemblies 11 according to this invention and includes, a conventional trailer frame 12 mounted on an axle 13 for supporting a pair of ground wheels 14 having a centrally disposed tongue 15 extending at right angles to the axle 13 and suitable attaching means, not shown, on the end of the tongue 15 for removable attachment to avehicle. The plurality of cradle mechanisms '11 are laterally supported and longitudinally spaced upon the frame 12 of the trailer 10, and are adapted as supports for the bottom surface of a boat, at points intermediate the bow and stem. Longitudinally spaced groups of holes 16 are provided at different points along the side rails 17 and 18 of the frame 12 for positioning the cradles 11 relative to each other and for adding or subtracting cradles from the trailer 10 as requirements dictate. Heretofore, different sizes of cradles were required for various sizes and shapes of boat hulls. This is expensive and requires the changing of cradles for different size boat hulls proposed to be carried.

Referring to FIG. 2, the boat cradle 11 consists of a mounting member or shaft 19 adapted for attachment to the side rails 17 and 18 of the frame 12 of a boat trailer 10 of the type mentioned above. It is understood that various other types of boat trailers may be employed, for instance, a pole type trailer wherein the shafts 19 are adapted to be supported at their centers instead of their ends as shown.

The mounting shaft 19 is suitably secured or joined to the frame 12, as by cap screws 20 at its opposed ends. A pair of fluid pressure bags 21 are rotatably mounted on, intermediate the ends of the mounting shaft 19 and are disposed in spaced relation thereon. It will be noted that the mounting shaft 19 not only supports the fluid pressure bags 21 for rotation relative thereto, but also serves as the main cross-member of the trailer frame 12. A boat 22 is fragmentarily shown disposed between the fluid pressure bags 21 showing the bags 21 coinciding with the particular angular inclination of the bottom of the boat 22.

The fluid pressure bags 21 are made of a rubber impregnated fabric or any other suitable material and are mounted on a hollow shaft 23 which is sleeved over the mounting shaft 19. More particularly, the fluid pressure bag 21 comprises a resilient, wheel-like body 24 which, although preferably an integral structure, as shown, may be formed from an outer annular tread and an inner concentric annular hub connected together as is common in the art. The bag 21 is secured to the hollow shaft 23 by flanges 25 and 26 so that one half of the bag 21 has the appearance of a doughnut in cross-section. The

- flange '25 is fixedly secured tothe hollow shaft 23 as by welding. The flange 26 is detachedly secured to the hollow shaft 23 for placing the body 24 thereon. An air valve 27 is provided in the body 24 for controlling the amount of pressure therein. Annular adjustable rings 28 are disposed adjacent each end of the shaft 23 for positioning the bags 21 relative to each other on the mounting shaft 19. Bushings 29 and 30 are disposed between the hollow shaft 23 and mounting shaft '19 at either end of the bag 21. It is to be noted that the longitudinal length of the air bag 21 is longer than the relatively large diameter thereof, thereby providing a large contact area for supporting a boat hull. The body 24 being made of a resilient material and filled with air pressure of a relatively low value, then results in a structure which will firmly and resiliently support a load without damage thereto and will adapt itself to various shapes of boat hulls without adjustment. This type of structure is not subjected to the compacting which would result from pure compression loading, and consequently, the bag 21 does not become hard under loads but remains resilient and, therefore, can absorb shock loads transmitted from a boat being transported over rough roads without damage there- The fluid pressure bags 21 as shown in FIG. 2 represent the deformation of the body 24 whensubjected to forces caused by a boat hull which is generally U- or V-shaped. In this instance the tread 31 of the body 24 is inclined downwardly at one end while the free edge or web 32 is deflected and somewhat buckled at its outer portion. A U- or V-shaped boat hull will tend 'to wrinkle the web 32 as shown in FIG. 2, and the tread 31 of the body 24 will be stressed about its juncture point 33 so as to lie flat along the surface of the boat hull 22. The boat hull 22 will then be supported both vertically and laterally mainly by the resilience of the tread 31 which is stressed and deflected inwardly toward the hollow shaft 23.

It will now be apparent that the novel boat cradle here in disclosed provides both lateral and vertical supports for a boat hull, the fluid pressure bags 21 readily conforming substantially to the configuration of the boat being carried and the resiliency thereof being unimpaired due to the fact that the bag 21 is not compacted under pressure exerted by the boat hull being carried. These cradles then will replace the highload, small area support points conventionally provided by the hard rubber rollers as is customarily used, with a large low pressure area closely fitting the hull shape.

It will be obvious that various changes in the details which have been herein described and illustrated in order to explain the nature of this invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

What is claimed is:

1. A boat trailer comprising the combination of a subing contour engage said rollers during loading and un- Istantially longitudinally extending trailer frame with suitable wheel and axle means for the mobility thereof, means on said frame for attachment to a drawing vehicle, a mounting shaft located transversely to the longitudinal axis of said frame and being carried by the frame, a pair of resilient fluid pressure filled rollers carried in spaced apart relation by said shaft to accommodate the keel of a boat therebetween, said rollers having a hollow baglike configuration with the axial length of each roller being substantially greater than the radius thereof so that when boat hulls of various size and constantly varyloading, the rollers will conform to the shape of the boat hulls and give both vertical and lateral support thereto over a large area and aid in centeringthe boat on the trailer, said rollers being susceptible to further resilient deformation to cushion the boat during transit of the trailer.

2. The boat trailer as defined in claim 1 wherein said rollers are rotatably mounted on. said mounting shaft.

3. The boat trailer as defined in claim 1 wherein said mounting shaft is adjustably secured to said frame.

4. The boat trailer as defined in claim 1 wherein said frame comprises spaced apart side rails to which the mounting shaft is secured.

'5. The boat trailer as defined in claim 1 wherein said rollers are adjustably positioned on said mounting shaft.

6. A boat trailer comprising the combination of a sub stantially longitudinally extending trailer frame with suitable wheel and axle means for the mobility thereof, means on said frame for attachment to a drawing vehicle, a mounting shaft located transversely to the longitudinal axis of said frame and being carried by the frame, a pair of resilient fluid pressure filled roller means carried in spaced apart relation by said shaft to accommodate the keel of a boat therebetween, each of said roller means having a total axial length substantially greater than the radius thereof so that when boat hulls of various size and constantly varying contour engage said roller means during loading and unloading, the roller means will conform to the shape of the boat hulls and give both vertical and lateral support thereto over a large area and aid in centering the boat on the trailer, said roller means being susceptible to further resilient deformation to cushion the boat during transit of the trailer.

References Cited in the file of this patent UNITED STATES PATENTS 710,936 Bacon Oct. 14, 1902 729,68'2- Selleck June 2, 1903 1,736,130 De Cloud Nov. 19, 1929 I 2,007,910 Stephens July.9, 1935 2,190,905 Welch Feb. 20, 1940 2,613,788 McLaughlin Oct. v14, 1952 2,716,499 Grant -Q Aug. 30, 1955 2,740,543 Moundsdon Apr. '3, 1956 2,860,792 Nelson et al. -4- Nov. 18, 1958 2,910,835 Timothy Nov. 3,1959

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