The rapid acceptance of forming hay into large cylindrical bales has not been matched with complementary development of means for the lifting, loading, or transportation of the bale so produced. This is of particular consequence because, depending upon the type of grass baled, cylindrical bales may weight between 1000 and 2000 pounds green and remain even as heavy as 1500 pounds when dry. Further, medium sized cylindrical bales typically range approximately five feet in diameter and approximately five feet in length. At this bulk and weight, prior practices of loading the baled hay by hand onto trucks or trailers are no longer practical.
The most popular expedient making use of common, currently available equipment is to employ a front end loader attachment mounted on a tractor. However, such systems require their own independent hydraulic and control systems, are time consuming to both mount and remove, and create frequent maintenance demands. Further drawbacks to the use of front end loaders as applied to loading and unloading of hay bales are that they are not standard equipment on the majority of farms and that a special procurement towards this use proves an expensive solution, both as to purchase and maintenance. Furthermore, agricultural tractors are not ordinarily designed to be heavily loaded at the front; they are usually much stronger at the rear.
In addition, several special handling devices have been developed, but none combines the simplicity, convenience and versatility necessary to effect a satisfactory solution.
The Nelson hay loading device disclosed in U.S. Pat. No. 2,954,886 is a fairly complex tractor mounted apparatus which teaches the use of gripping jaws to engage a bale and a hydraulically actuated swinging extension to rotate the bale from a position beside the tractor to an elevated position from which the bale may be dropped onto an elevated surface behind the tractor. The apparatus is not suitable for conveniently unloading hay bales from an elevated surface, nor for applications requiring more careful placement than the "dropping" operation allows. The operation contemplated by Nelson requires an independent hydraulic system operating from a rigid, stationary hitch and the resulting design is not adaptable to a configuration that is readily attachable to a standard, hydraulically actuated three point hitch.
Cox, in U.S. Pat. Nos. 4,099,629 and 4,015,739, discloses a hay bale handling machine, including one configuration to be mounted on a tractor. His primary disclosure is of a device that may be mounted into the bed of a pickup truck. This pickup truck apparatus uses an extended spear to impale a bale of hay and then pivots the immediate upright member from which the spear protrudes until the spear is essentially vertical at which point the bale is in a cylindrically upright position, resting over the truck bed upon the previously upright and now horizontal spear carring member. This configuration does not allow either loading or unloading hay bales upon any appreciably elevated surface. The disclosures also contain a configuration for mounting the spear upon a three point hitch behind a tractor, but again the device is not appropriate to work with elevated storage or transportation surfaces. The spear is mounted upon an upright post which is directly attached to the three point hitch system. The top of the post is attached through a top support arm to the upper hitch point of the tractor. The bottom of the post is shown permanently affixed to a drawbar disposed between the lower hitch members. Both the top support arm and the drawbar are standard means for attaching implements to a three point hitch and neither is directly adaptable for mounting the post and spear in a configuration that allows loading or unloading from elevated surfaces. Rather it is the object of Cox to engage and tilt the bale for transportation only upon the spear or spike itself, and not for loading to or unloading from elevated surfaces.
The identical failings are present in the Jones disclosure for U.S. Pat. No. 4,120,405. Indeed, here the inadequacies of the three point hitch configuration seems to be conceded as this system is discussed anciliary to a front end loader adaptation for handling hay bales. But even as adapted, the front end loader retains the inadequacies discussed in the preceding for standard, commercially available front end loaders.
The tractor mounted embodiment of McFarland's U.S. Pat. No. 4,084,707 is primarily of interest in unrolling hay bales, though it may be used for transport in the same sense as the Cox device. However, it too is fundamentally lacking for the immediate application.
Further, while various elevating extension schemes have been developed to be mounted upon a tractor's three point hitch, none is appropriate for the contemplated use.
A shovel device is disclosed by U.S. Pat. No. 4,068,774, however Howell's apparatus is not adaptable because it teaches a single extension bar device. Such a one-bar system could not produce an appropriate tilt of an engagement spear.
The Larsen device, under U.S. Pat. No. 2,311,671 shows a manure loader. This device includes complications which were appropriate to facilitate a dumping action, but are not appropriate for a hay bale loading machine where dumping is not contemplated. Further, the structural bar system itself disposes a lower bar so low as to unduly limit an approach to an elevated platform.
The Holopainen ditch digging device disclosed in U.S. Pat. No. 2,496,874 is an inappropriate elevating extension in the present application for the same reasons as Larsen. In addition, the Holopainen system calls for auxiliary hydraulic systems.