Abstract:
A leveling and support system for recreational vehicles uses fluid cylinders located at predetermined positions on the recreational vehicle, driven by a master cylinder through a valving control system. The piston of the master cylinder is actuated by a motor driven or hand crank driven screw mechanism, so that a recreational vehicle can be supported or leveled by a single drive unit with controls operated from a single control position.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to recreational vehicles and especially to a system for leveling and supporting a recreational vehicle utilizing fluid actuated cylinders driven from a master cylinder. 
     2. Description of the Prior Art 
     A variety of recreational vehicles is available on the market including small and large campers for attachment to the back of a family automobile for camping for short or extended periods of time; large motor homes and fifth wheel campers which do not have front wheels and are suspended by a &#34;fifth wheel&#34; to the back of a pick-up truck. This latter vehicle requires front end support when disconnected from the truck. 
     One of the problems encountered by most recreational vehicles is supporting the front end or tongue of the camper when the recreational vehicle is disconnected from the family car or other towing vehicles. The support must be adjustable to allow the vehicle to be adjusted for different heights to maintain the inside of the recreational vehicle level. 
     In addition, on the smaller campers, springs are such that the campers tend to be unstable and shake considerably when positioned in a campground. These problems are dealt with by hand actuated jacks which may be placed under the tongue of a camper, or mounted to the front portion of the fifth wheel camper, and which may be hand actuated to raise or lower the front portion of the vehicle. On smaller campers that tend to be unstable, a series of smaller hand operated jacks are sometimes positioned on the four corners and each jack operated to get the camper level and supported by the jacks so that the camper will not rock when walking from one side to the other of the camper. 
     In addition to the hand actuated jacks that are commonly used or supplied with recreational vehicles, auxiliary jacks have been available which are actuated by electric motors for raising and lowering a portion of the vehicle. These, however, require connection to electrical power and are expensive to purchase as an option to the recreational vehicles. Finally, large semi-trailers having fifth wheels have air over hydraulic jacks for supporting the trailers when disconnected from the cab portion and which are actuated by the truck&#39;s air system. 
     TYPICAL PRIOR ART 
     Inventions which use hydraulic jacks, or the like, may be seen in the following U.S. Pat. Nos. 
     3,350,063 --Thurlow, 
     4,052,073--Franchin, 
     3,697,044--Kowalski, 
     3,709,467--Mann, 
     3,758,074--Jeffries, 
     3,409,272--Rasmussen, 
     3,338,554--Gostomski, 
     3,567,271--Gostomski, 
     3,698,758--Dodgen, 
     3,640,502--Bargman, 
     3,360,141--Martin, 
     3,415,490--Steele, 
     3,955,797--Richards. 
     In addition, my prior U.S. Pat. No. 4,082,249, for a recreational vehicle leveling and support system, has a connection for a source of water under pressure which is connected to a plurality of water cylinders connected to the recreational vehicle and predetermined positions through a main valve and through one branch valve for each water cylinder. The main valve and the branch valves are used to raise and lower parts of the recreational vehicle from the pressure of a community water supply or a recreational vehicle water tank. This provides an inexpensive, reliable leveling and support system but is subject to the water freezing in very cold climates during mid-winter months. To overcome this, my prior patent provides means for draining the cylinders and locking the cylinder rods in place when the system is not in use. The use of a community water supply for lifting or squeezing derives from my prior U.S. patent application Ser. No. 805,895 for a Fluid System for Compacting and Squeezing, now U.S. Pat. No. 4,121,512. The present invention, on the other hand, provides an improved fluid level and support system, in which the individual cylinders are driven through control valves by a master fluid cylinder, which acts as a closed fluid system and therefore may have antifreeze in the fluid or otherwise be a fluid not subject to freezing except in very cold climates. The master cylinder piston is in turn driven by a screw push/pull instrument so that a mechanical advantage is gained from both the screw pushing and pulling instrument and the hydraulic cylinder. Since a closed system is involved, pushing the piston and the master cylinder in one direction extends the individual hydraulic cylinders and retracts the individual cylinders when the piston is pulled in the other direction. Each individual cylinder can be locked in a predetermined position by closing its valve. Since the fluid is not generally compressible, it locks the cylinder in place until the valve is opened again. 
     SUMMARY OF THE INVENTION 
     A recreational vehicle leveling and support system has a master fluid cylinder having a piston located therein and a piston rod attached to the piston and extending therefrom. A plurality of fluid lifting cylinders is positioned in a spaced relationship to each other and mounted on a recreational vehicle in predetermined positions. The master cylinder is connected to each lifting cylinder through a control valve so that each valve can be operated individually. The control valves can be located at a predetermined control center for controlling different positions on the recreational vehicle from a single point. A rotable drive screw is coupled to the master cylinder piston rod for pushing and pulling the piston to actuate the master cylinder in each of the individual lifting cylinders, so that a recreational vehicle can be supported and leveled with the lifting cylinders from a single control point. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features and advantages of the present invention will be apparent from the written description and the drawings in which: 
     FIG. 1 is a perspective view of a recreational vehicle incorporating a preferred embodiment of the present invention; 
     FIG. 2 is a fragmentary exploded sectional view of the master cylinder and drive system; 
     FIG. 3 is a sectional view taken on the line 3--3 of FIG. 2; 
     FIG. 4 is a diagrammatic view of the control system of the present invention; 
     FIG. 5 is a sectional view of the master cylinder and its mounting bracket; 
     FIG. 6 is a fragmentary sectional view of the mounting bracket and cylinder locking system of the present invention; and 
     FIG. 7 is a side sectional view of the cylinder locking system of FIG. 6. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings and especially to FIG. 1 a recreational vehicle 10 is seen having a frame 11 and wheels 12 mounted thereto and an entry doorway 13. Recreational vehicle 10 has a forward tongue 14 and a plurality of windows 15. The vehicle has mounted thereto a master fluid cylinder 16 which is mounted horizontal and parallel to the frame or chassis 11. The master cylinder 16 has a pushing or pulling drive system 17 which may be driven with a hand crank 18 in one embodiment of the present invention, but, typically would have an electric motor mounted thereto for driving the master cylinder 16 with the option to use a hand crank 18 in an emergency. The master cylinder 16 is connected through a master control or valving manifold 20 having a plurality of valves 21 mounted to the tongue 14. The tongue may also have a tongue jack 22 mounted thereto but does not form a part of the present invention. The control manifold 20 is in turn connected to a plurality of individual leveling and supporting cylinders 23 which may be placed on the front to support the front end of the recreational vehicle 10 or spaced at all four corners for supporting and leveling the camper at a campsite. Each lifting cylinder 23 has a cylinder rod 29 and may have a foot 25 on the bottom thereof. The operation may more clearly be understood in connection with FIGS. 2, 3 and 4 in which the hydraulic cylinder 16 has a fitting 24 at one end for hydraulic tubing, for connecting to the manifold 20 of FIG. 4. Cylinder 16 also has a flange 25 for bolting to a flange 26 of the push-pull drive mechanism 27. A piston 28 has a seal 30 and fits into the cylinder 16 but is bolted with a bolt 31 to an extendable and retractable inner casing or tube 32. Tube 32 extends inside an outer casing 33 of the push-pull drive mechanism 27. Inside the inner casing 32 is an elongated threaded shaft 34 which rides in bushings 35 at each end of the housing 33. The threaded shaft 34 has a screw shaft receiving an indexing head 39 at one end for rotating the threaded shaft 34 and the bushings 35. Rotation of the shaft 34 will drive the inner casing nut 36 which may have internal acme threads therethrough for engaging the teeth of the threaded shaft 34. The nut 36 is welded or fixedly attached to the inner casing 32 so that rotation of the shaft 34 will move the nut 36 and the inner casing 32 to drive it into or out of the outer casing 33. 
     Outer casing 33 has an elongated rib portion 37 protruding from one edge as shown in FIG. 3 adjacent an elongated groove 40 formed in the inner housing 32 so that a cylindrical or spherical key 49 can fit between the grooves formed in inner housing 32 and the outer casing 33 to prevent the rotation of inner housing 32 when the thread shaft is rotated, so that the nut 36 and housing 32 are driven linearly. This, in turn, drives the piston 28 to push or pull the piston depending upon the direction of rotation of the shaft 34. Shaft 34 is driven by the screw shaft receiving head 39 which may be engaged by a self indexing gear motor shaft 41 which is connected to a twelve volt D.C. motor 42, which can be actuated in the forward or reverse direction by switch 43. The motor 42 has a sleeve 44 which may extend over the outer casing 33 and may be slipped so that a hand crank 45 having a gear mating shaft 46 can engage the receiving indexing head 39 for hand cranking shaft 34 for driving the piston 28 in either direction depending upon the direction of rotation of the hand crank 45. This arrangement allows for the mechanical advantage of the threaded shaft 34 in combination with the mechanical advantage gained by the fluid or hydraulic cylinder 16 while at the same time allowing the control of all of the individual slave cylinders 23 through individual lines 47 to the control manifold 20 having valves 21 for controlling each line 47 and each lifting cylinder 23. A main fluid line 48 connects the manifold 20 to the master cylinder 16 which can be driven with the motor 42 and the hand crank 45. The electric motor 42 is actuated in either a forward or reverse direction by the switch 43, so that the individual valves 21 for each individual cylinder 23 can be controlled at a central location. Switch 43 and the manifold 20 with the valves 21 are located adjacent each other so that raising or lowering each of the cylinders 23 can be simultaneous or each can be controlled individually for leveling the camper on all four corners. 
     The master cylinder 16 and drive assembly can have a frame mounting bracket 50 attached to one side thereof, with a frame bracket bolt 51, so that the bracket can be attached to the chassis 11 of FIG. 1 without welding. Similarly, the individual slave cylinders can have a mounting bracket 52 as seen in FIGS. 6 and 7 attached thereto with a mounting bracket pin 53 which may be fixedly attached to the bracket 52 with a cylinder 23 riding thereon and held by cotter pin 54. A cylinder locking pin 55 can have a handle 56 at one end and might have a spring 57 mounted inside a hollow sleeve 58 at one end of the cylinder 23. The locking pin 55 can be slipped into an opening 60 in the bracket 52 for locking piston 28 in a vertical position or the cylinder 23 can be swung 90° for locking the pin 55 in either openings 61 for a horizontal storage position. The spring 57 holds the pin 55 in its locked position until the handle 56 is pulled, pulling the pin 55 against the spring 57 to unlock the piston 28 which can then rotate on the pin 53. Bracket 52 also has a frame locking bolt 62 for locking to frame 11 of the camper 10 in any position desired. It should, of course, be clear that the cylinders can be welded to the frame if desired, but in the after market, a detachable bracket is desirable. 
     It should be clear at this point that a recreational vehicle leveling and support system has been provided which is easily adapted to fit a wide variety of recreational vehicles. It will also be clear to those skilled in the art that the cylinders and components can be made of aluminum, steel or in the case of the individual lifting cylinders, a polymer material can be utilized without departing from the spirit and scope of the invention. Similarly, any fluid such as hydraulic fluid, can be utilized in the system, even though water with an antifreeze therein can be used without departing from the scope of the invention. Many of the parts are commercially available and reference may be had to my prior U.S. Pat. No. 4,082,249 for cylinder details. The present invention is accordingly not to be construed as limited to the particular forms shown which are to be considered illustrative rather than restrictive.