Abstract:
An adjustable hitch device for coupling a towing vehicle to a towed implement or trailer is adapted for changing the coupling angle between the vehicle and the implement and also for changing the elevation angle of the implement. An elongated, rigid link is pivotally coupled at a first end to a hitch mechanism coupled to the vehicle and at a second, opposed end to a forward portion of the implement. An intermediate portion of the link is pivotally coupled to one end of a hydraulic cylinder, while a second, opposed end of the hydraulic cylinder is coupled to a forward portion of the implement. Extension of the cylinder lowers the implement&#39;s forward portion and raises its aft portion, while retraction of the cylinder has an opposite effect. In this manner, the height of the implement may be increased for use in operation or may be lowered for transport or storage.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to an arrangement for towing an implement or a trailer by a vehicle, and is particularly directed to an adjustable hitch arrangement for changing the angle of elevation, or inclination, of the implement or trailer relative to the ground plane to an increased elevation angle for use during operation of the implement or trailer, or for reducing the implement&#39;s elevation angle for transport or storage of the implement or trailer. 
     BACKGROUND OF THE INVENTION 
     Grain such as wheat, shelled corn, oats and other granular materials are commonly transported from point to point by means of conveyors. The movement of the grain may be from a combine or a grain cart to a truck or a storage bin, or between storage bins. This grain movement typically involves elevating the grain from a lower portion of a first grain storage arrangement to an upper portion of a second grain storage arrangement. This is typically accomplished by means of a grain conveyor with a moving endless belt disposed within an elongated, tubular housing. The transport vehicles and storage bins are of various sizes and heights. Therefore, the upper discharge end of the grain conveyor must be capable of assuming a range of heights to accommodate various vehicle and storage bin sizes. 
     The conveyor&#39;s housing enclosing the moving endless belt is commonly supported by an adjustable frame of the scissors type connected to an intermediate portion of the tubular housing to raise and lower its upper discharge end. Another approach uses another type of adjustable frame slidably coupled to the elongated, tubular housing adjacent its discharge end. The adjustable frame is adapted for movement along the lower surface of the conveyor&#39;s tubular housing to change its angle of elevation and the height of its upper discharge end. These types of conveyor housing supports are typically rather complex, involving various moving parts, require a flat surface over substantially the entire length of the conveyor housing, and have a separate, independent power system for raising and lowering the conveyor&#39;s housing. In addition, the size and complexity of the conveyor housing support assembly restricts the compactness of the conveyor for transport and storage. 
     The present invention addresses the aforementioned limitations of the prior art by providing an adjustable hitch device for use with a towed implement or trailer which is capable of elevating the implement or trailer to increased heights, while also allowing the implement or trailer to assume a lower profile to facilitate implement transport and storage. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an adjustable hitch mechanism for towing a portable implement or a trailer which allows for increasing the angle of elevation of the implement/trailer for operation at increased heights, or decreasing the implement/trailer&#39;s angle of elevation to reduce its profile to facilitate transport and storage. 
     It is another object of the present invention to provide a hydraulic arrangement for towing a portable implement or trailer which allows for changing the implement/trailer&#39;s elevation angle for use in operation or for towing/storage of the implement/trailer, where the hydraulic arrangement is powered by either the implement/trailer&#39;s hydraulic system or by the hydraulic system of the towing vehicle in parallel. 
     Yet another object of the present invention is to provide a hydraulic towing arrangement which is adapted for use with an implement or a trailer, and is particularly adapted for use with a portable seed handling conveyor which allows for adjusting the elevation of the conveyor between increased elevation for use in operation in elevating and discharging seeds, and reduced elevation for transport and storage of the conveyor. 
     A still further object of the present invention is to provide an adjustable hydraulic towing arrangement adapted for use with a wide range of trailers and agricultural implements, and which is particularly adapted for use with seed handling conveyors for positioning the conveyor at an increased elevation angle for lifting the grain to greater heights during operation, or for reducing the conveyor&#39;s elevation angle while increasing the ground clearance of the adjustable towing arrangement to facilitate conveyor transport and storage. 
     For use in towing a portable grain conveyor having forward and aft portions and including a conveyor arrangement movable between an elevated position for use in conveying grain and a lowered position for transport and storage, the present invention contemplates an adjustable hitch comprising: a tongue attached to and extending rearwardly from a traction vehicle; a rigid arm having a forward portion pivotally coupled to the tongue and extending rearwardly from the traction vehicle, the rigid arm further including an aft portion pivotally coupled to the forward portion of the grain conveyor, wherein the rigid arm is free to pivot up and down in a generally vertical direction relative to the tongue and the grain conveyor; and a displacement member movable between extended and retracted configurations and having a forward portion pivotally coupled to an intermediate portion of the rigid arm and an aft portion pivotally coupled to the grain conveyor, wherein movement of the displacement member to the extended configuration lowers the forward portion of the grain conveyor and elevates the conveyor arrangement for use in conveying grain, and movement of the displacement member to the retracted configuration raises the forward portion of the main conveyor and lowers the conveyor arrangement for transport and storage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The appended claims set forth those novel features which characterize the invention. However, the invention itself, as well as further objects and advantages thereof, will best be understood by reference to the following detailed description of a preferred embodiment taken in conjunction with the accompanying drawings, where like reference characters identify like elements throughout the various figures, in which: 
         FIG. 1  is a perspective view of a portable grain conveyor particularly adapted for use with the adjustable hitch device of the present invention; 
         FIG. 2  is a side elevation view illustrating details of the installation of the adjustable hitch device in a portable grain conveyor in accordance with the present invention; 
         FIG. 3  is a side elevation view illustrating the adjustable hitch device in the upraised position for lowering the discharge end of the conveyor; 
         FIG. 4  is a side elevation view illustrating the adjustable hitch device in the lowered position for raising the discharge end of the conveyor; 
         FIG. 5  is a simplified schematic diagram of a hydraulic system for controlling the operation of the adjustable hitch device of the present invention; and 
         FIGS. 6   a , 6   b  and  7   a , 7   b  illustrate a comparison of the height of a portable grain conveyor incorporating the adjustable hitch device of the present invention and the height of a portable grain conveyor without the inventive adjustable hitch device in the full retracted configuration and in the full upraised configuration, respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , there is shown a perspective view of a portable grain conveyor  10  in which the adjustable hitch device of the present invention is adapted for use. Portable grain conveyor  10  includes a secondary conveyor  12  having a grain hopper  14  attached to its lower end. Hopper  14  is adapted to receive grain which is provided to and transported upwardly by the secondary conveyor  12  to its upper end. The upper end of secondary conveyor  12  is disposed adjacent the inlet end  16  of the portable grain conveyor  10 . The inlet end  16  of the portable grain conveyor  10  includes a second grain hopper  40  (shown in  FIG. 2 ) adapted to receive the grain discharged from the upper end of the secondary conveyor  12 . Attached to and extending upward from the portable grain conveyor&#39;s inlet end  16  is a primary conveyor  20  which includes a lower tubular housing  20   a  and an upper tubular housing  20   b  which are connected together in an end-to-end manner. An intermediate portion of the primary conveyor  20  is attached to and supported by a flexible support frame  24 , also known as a “scissors” support frame. Incorporated within flexible support frame  24  is one or more hydraulic cylinders  26  movable between a retracted configuration and an extended configuration. With hydraulic cylinder  26  retracted, primary conveyor  20  is lowered to a substantially horizontal orientation for transport or storage of the portable grain conveyor  10 . With hydraulic cylinder  26  extended, as shown in  FIG. 1 , primary conveyor  20  is oriented in the use position for operation in transporting grain upwardly and discharging the grain from its outlet discharge end  30 . Attached to a lower portion of flexible support frame  24  are a pair of wheels  28  to facilitate transport of the portable grain conveyor  10 . A similar pair of wheels is attached to a lower end of the secondary conveyor  12  to facilitate its positioning of the secondary conveyor. Guy wires, or cables, or solid trussing  32  extend substantially the length of the primary conveyor  20  to provide support for and alignment of its lower and upper housings  20   a ,  20   b.    
     Each of the primary and secondary conveyors  20 ,  12  includes a respective endless belt (not shown) for transporting grain. In some cases, these endless belts may be provided with plural spaced cleats extending outwardly from the belt which allow these belts to transport increased amounts of grain at increased elevation angles of the two conveyor sections. In some cases, the conveyor angle of elevation may approach, and even exceed, 40°. 
     Referring to  FIG. 2 , there is shown a side elevation view of the inlet, or front, end  16  of a portable grain conveyor incorporating an adjustable hitch device  52  in accordance with the present invention. The inlet end  16  of the portable grain conveyor includes a conveyor coupling housing  54 . Mounted to an upper portion of the conveyor coupling housing  54  is a second grain hopper  40  adapted to receive grain from the secondary conveyor, which is not shown in  FIG. 2  for simplicity. Disposed on the distal end of lower tubular housing  20   b  is its outlet discharge end  30  described above and shown in  FIG. 1 . Attached to the second grain hopper  40  is a power take-off (PTO) drive shaft  42 . PTO drive shaft  42  is coupled to the PTO output (not shown) of a traction vehicle, such as a tractor,  44  to which the inlet end  16  of the portable grain conveyor  10  is connected as described below. PTO drive shaft  42  is used to drive the endless belt which transports the grain within the primary conveyor  20 . 
     Attached to an aft portion of a tractor  44  adjacent its rear drive wheels  46  is a mounting structure  48 . Attached to mounting structure  48  and extending rearward therefrom is a connecting, or hitch, arrangement for securely coupling the portable grain conveyor&#39;s inlet end  16  to tractor  44 . The hitch arrangement includes a tractor tongue  50  mounted to and extending rearwardly from the tractor&#39;s mounting structure  48 . Pivotally attached to tractor tongue  50  by means of a coupling pin  60  is a coupling member  58 . Coupling member  58  is free to pivot horizontally with respect to the tractor&#39;s tongue  50 . Coupling member  58  is pivotally connected to a forward end of an elongated, rigid coupling arm  56  by means of a first forward pivot pin  62 . Coupling arm  56  forms a part of the adjustable hitch device  52  of the present invention. An aft end of coupling arm  56  is pivotally coupled to a forward portion of the portable grain conveyor&#39;s inlet end  16  by means of a second aft pivot pin  64 . By means of the first forward and second aft pivot pins  62 ,  64  coupling arm  56  is capable of undergoing vertical displacement with respect to tractor tongue  50  and the portable grain conveyor&#39;s coupler housing  54  which forms part of the portable grain conveyor&#39;s inlet end  16 . 
     Adjustable hitch device  52  further includes a hydraulic cylinder  51 . A first, rod end of hydraulic cylinder  51  is coupled to an intermediate portion of coupling arm  56  by means of a third forward pivot pin  53  inserted through a first bracket  36  attached to the coupling arm. A second, piston end of hydraulic cylinder  51  is coupled to a forward portion of the portable grain conveyor&#39;s coupler housing  54  by means of a fourth aft pivot pin  55  inserted through a second bracket  34  attached to the coupler housing. The aforementioned brackets  34 ,  36  may be attached to or formed integrally with the coupler housing  54  and coupling arm  56 , respectively. 
     A first pair of hydraulic hoses  66  is connected between the hydraulic system of tractor  44  and a hydraulic manifold  70  attached to the portable grain conveyor&#39;s coupler housing  54 . A second pair of hydraulic hoses  68  couples the hydraulic manifold  70  to the hydraulic cylinder  51  of the adjustable elevation hitch device  52 . A third pair of hydraulic hoses  69  coupled to hydraulic manifold  70  provides hydraulic power to the one or more hydraulic cylinders  26  connected to the portable grain conveyor&#39;s flexible support frame  24  as shown in  FIG. 1  and described above. 
     The operation of the adjustable hitch device  52  of the present invention will now be described in terms of  FIGS. 3 and 4 .  FIGS. 3 and 4  are side elevation views of the adjustable hitch device  52  respectively shown with its hydraulic cylinder  51  in the fully retracted position and in the fully extended position. With hydraulic cylinder  51  of the adjustable hitch device  52  in the fully retracted position as shown in  FIG. 3 , the bottom of the portable grain conveyor&#39;s coupler housing  54  is positioned a distance “X” above the ground  82 . In this configuration, the portable grain conveyor&#39;s coupler housing  54  is disposed higher than tractor tongue  50  relative to the ground  82 . In this configuration, coupling arm  56  extends upwardly in proceeding from tractor tongue  50  toward the portable grain conveyor&#39;s coupler housing  54 . 
     With hydraulic cylinder  51  fully extended as shown in  FIG. 4 , the forward end portion of coupling arm  56  attached to the combination of tractor tongue  50  and coupling member  58  by means of pivot pin  62  has not changed its position when compared with its position shown in  FIG. 3 . However, the opposing, or aft, end of coupling arm  56  pivotally connected to the portable grain conveyor&#39;s coupler housing  54  has been displaced downwardly. With the portable grain conveyor&#39;s coupler housing  54  moved closer to the ground  82 , such that the distance between the ground and the coupler housing is now “Y”, where Y is &lt;X, the lowering of the coupler housing results in a corresponding increase in the height above the ground of the opposing end of the portable grain conveyor  10  where the grain is discharged from the conveyor. This increase in height in the discharge end of the portable grain conveyor  10  can be as much as 9 feet for a portable grain conveyor on the order of 70 feet in length. Returning to the retracted position of hydraulic cylinder  51  as shown in  FIG. 3 , not only is the vertical height, or profile, of the portable grain conveyor reduced, but the distance between the ground  82  and the adjustable elevation hitch device  52  is increased over that shown in  FIG. 4 , to facilitate transport and storage of the portable grain conveyor. 
     Referring to  FIG. 5 , there is shown a simplified schematic diagram of a hydraulic system  72  for operating the adjustable hitch device  52  of the present invention. Hydraulic system  72  includes a hydraulic pressure source  74  coupled to hydraulic hitch cylinder  51  and to first and second lift cylinders  26   a  and  26   b . Hydraulic fluid under pressure is provided via a hydraulic input line  76   a  to the piston sides of the hydraulic hitch cylinder  51  and the first and second hydraulic lift cylinders  26   a  and  26   b . In response to this hydraulic pressure, the rod of the hydraulic hitch cylinder  51  is moved to the extended position as shown in  FIG. 4  for lowering the conveyor coupler housing  54 , or the inlet end  16  of the portable grain conveyor  10 . With the discharge end of the portable grain conveyor  10  in an elevated position, the hydraulic fluid is then provided to the respective piston sides of the first and second lift cylinders  26   a  and  26   b  to further elevate the discharge end of the portable grain conveyor to the fully upraised position. Upon removal of hydraulic fluid under pressure from the hydraulic lift and hitch cylinders, the three hydraulic cylinders retract and hydraulic fluid returns via a hydraulic return line  76   b  first from the rod ends of the first and second lift cylinders  26   a ,  26   b  and then from the rod side of the hydraulic lift cylinder  51  to the hydraulic pressure source  74 . This results in retraction of the hydraulic lift cylinder  51 , raising of the inlet end  16  of the portable grain conveyor  10 , and lowering of the discharge end of the portable grain conveyor. Following retraction of the first and second lift cylinders  26   a ,  26   b , hydraulic fluid under pressure is applied to the rod end of the hitch cylinder  51  causing retraction of the cylinder and raising of the conveyor&#39;s inlet end  16 . 
     Referring to  FIGS. 6   a ,  6   b  and  FIGS. 7   a ,  7   b  there is shown a portable grain conveyor  84  without the inventive adjustable hitch device and a portable grain conveyor  86  incorporating the adjustable hitch device of the present invention in the full retracted configuration and in the full upraised configuration, respectively. As shown in  FIGS. 6   a  and  6   b , the portable grain conveyor  86  incorporating an adjustable hitch device in accordance with the present invention has the same profile as the conventional conveyor  84  shown in  FIG. 6   a , but the inventive conveyor shown in  FIG. 6   b  provides more horizontal reach from the tires to the discharge end of the conveyor. By allowing the conveyor&#39;s transport wheels to be moved closer to the inlet end  16  of the portable grain conveyor  10 , the conveyor&#39;s discharge end  30  can also be positioned at greater heights as shown in the figures. This feature also facilitates transport and storage of the portable grain conveyor  86  incorporating the invention as compared with the other portable grain conveyor  84 . Thus,  FIGS. 7   a ,  7   b  show that the portable grain conveyor  86  incorporating the inventive adjustable hitch device is capable of achieving higher elevations, by more than  7  feet, than the similarly configured portable grain conveyor  84  which does not include the adjustable hitch device of the present invention. 
     While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the relevant arts that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications that fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.