Abstract:
A hydraulically-operated grapple attachment for the scoop bucket of a skid steer loader comprises a mounting bar running the length dimension of the bucket along a top rear edge thereof and pivotally attached to the mounting bar by tubular steel arms is a crossbar member having perpendicularly oriented tines projecting downward therefrom where at least one of the tines is hydraulically displaceable in a direction forward from the crossbar. Actuation of the hydraulically-movable tine serves to prevent the skid steer loader from becoming mired.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    I. Field of the Invention 
         [0002]    This invention relates generally to an attachment for a skid steer loader-type work vehicle, and more particularly to a hydraulically-actuated grapple for use in handling compacted silage. 
         [0003]    II. Discussion of the Prior Art 
         [0004]    For many years, dairy farms have stored corn stalks and other forage plants as silage in tall, vertical tanks called silos. The plant material is collated, chopped into pieces and fed into a stationary machine called as “silo filler” that would further chop the stalks and blow them up a narrow tube to the top of a tower silo. Current technology uses mechanical forage harvesters that collect and chop the plant material, and deposit it in trucks or wagons. These forage harvesters can be either tractor-drawn or self-propelled. They blow the silage into the wagon via chute at the rear or side of the machine. Silage may also be emptied into a bagger, which puts the silage into a large plastic bag that is laid out on the ground. Typically, these bags may have a diameter anywhere from four to ten feet and may be 200 feet or more in length. 
         [0005]    Silage undergoes anaerobic fermentation, which typically starts about 48 hours after the bag is filled. The process converts sugars to acids and exhausts an oxygen present in the crop material. Fermentation is essentially complete after about two weeks. When bagging of silage is employed, it must be firmly packed to minimize the oxygen content or it will spoil. 
         [0006]    The ensiled product retains a much larger proportion of its nutrients than if the crop had been dried and stored as hay or stover. Bulk silage is commonly fed to dairy cattle. Common forages converted to silage include several varieties of grasses, herbaceous legumes, alfalfa and sorghums. When the silage is loaded into silage bags, the material becomes highly compacted and tightly contained so as to minimize oxygen exposure. As such, the material within the bag becomes somewhat entangled and solid in its texture. 
         [0007]    When it is desired to remove the compacted silage from the bag in quantities sufficient to feed, say, a herd of say 50 cows, front end loaders, also referred to as skid steer loaders, may be used to remove a quantity of silage and load IT onto a truck for transport to a feeding site. It has also been a practice to incorporate a hydraulic grapple onto the bucket of a skid steer loader to facilitate separating silage from the compacted mass and loading the separated quantity into the bucket of the skid steer loader. The process starts at one end of the elongated bag and before too long, the ground on which the skid steer loader must operate becomes quite slippery from the moist silage and the weather. As a result, the skid steer loader wheels frequently loose traction and the vehicle can become stuck, especially where the grapple tines are embedded in the tightly compacted silage. It may then become necessary to dump the full bucket or hook up the skid steer loader to a truck being loaded using a chain to pull it free from the compacted silage. This, of course, takes time that can be better spent on other chores. 
         [0008]    The present invention provides a novel and non-obvious solution to the aforementioned problem. 
       SUMMARY OF THE INVENTION 
       [0009]    A grapple attachment for a bucket of a skid steer loader comprises a crossbar pivotally affixed to the scoop bucket where the crossbar supports a plurality of parallel tines and a hydraulic actuator for rotating the crossbar and tines between a raised state and a lowered state with respect to an open top and front of the scoop bucket. The grapple attachment is characterized in that at least one of the plurality of parallel tines is connected to a piston rod of a hydraulic cylinder which, when actuated, advances the one tine outward from the crossbar and beyond the row of fixed tines mounted on the crossbar. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0010]    The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several views refer to corresponding parts: 
           [0011]      FIG. 1  is a perspective view of a grapple attachment for a skid steer loader work vehicle embodying my invention; 
           [0012]      FIG. 2  is a cross-sectional view taken through one of the pivot arms and showing a hydraulic actuator contained therein; 
           [0013]      FIG. 3  is an end view of the preferred embodiment with the grapple shown in its raised position in ghost line and in its lowered position in solid line; and 
           [0014]      FIG. 4  is an end view showing the movable tines extended relative to the fixed tines. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]    This description of the preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom” as well as derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “join” and “joining” are used interchangeably and refer to one structure or surface being secured to another, structure or surface or integrally fabricated in one piece, unless expressively described otherwise. 
         [0016]    Referring first to  FIG. 1 , there is indicated generally by numeral  10  a grappling attachment constructed in accordance with the present invention. It is shown as being attached to the hydraulically-activated arms  12  and  14  of a skid loader work vehicle (not shown). While also not shown in  FIG. 1 , the grapple assembly  10  incorporates the conventional quick connect coupler rather universally used for joining various attachments to the hydraulically-operated arms  12 ,  14  of the skid steer loader. 
         [0017]    The grapple is seen to comprise a scoop bucket  18  having a bottom surface  20 , a rear surface  22  and triangularly shaped side surfaces  24  and  26  wherein the hypotenuse of each triangle extends from an upper edge  28  of the rear surface to a front edge  30  of the bottom surface  20 . The scoop bucket is of a welded construction and preferably made from 2¼ inch gauge cold rolled steel. Extending along the length dimension of the upper edge  28  is a steel tube of rectangular cross-section  32  that is affixed to the scoop bucket  18  by welded end brackets  34  and  35 . 
         [0018]    The grapple of the present invention further includes a crossbar member  36  to which is attached a plurality of teeth or tines  38  . . .  48  and which extend perpendicularly thereto. More particularly, the tines  38  . . .  48  are removably secured to the crossbar  36  by U-shaped brackets  50  . . .  60  that are welded to the crossbar and which surround three sides of the tines. Bolts passing through the brackets and tines hold the tines in place. 
         [0019]    The crossbar member  36  is pivotally connected to the rectangular tube  32 . More particularly, tubular steel arms  62  and  64  of rectangular cross-section are welded at a first end to the crossbar member  36  and are connected by braces  65  and  67 . The arms  62  and  64  are pivotally connected to the rectangular tube  32  that extends along the length dimension of the scoop bucket by a clevis connection, as at  66 , having a hinge pin  68  that acts as the axis of rotation for the crossbar member  36  and its attached tines. The tubular arm  64  attaches to the crossbar member  36  and to the rectangular tube  32  in an identical manner as the tubular arm  62 . 
         [0020]    In  FIG. 1 , the crossbar and its attached tines are shown in a closed or lowered position relative to the bottom surface  20  of the scoop bucket  18 . Hydraulic cylinders or actuators, as at  70  and  72 , are deployed so as to be able to lift and rotate the crossbar and tines clockwise when viewed as in  FIG. 1  so that the tines no longer block the otherwise open front of the scoop bucket  18 . To achieve this result, a pair of ears  74  and  76  is welded to the crossbar member  36  that are spaced apart from one another so as to receive therebetween a coupler  78  fastened to the end of a piston rod  80  of a hydraulic actuator  70 . A hinge pin  84  pivotally couples the coupler  78  to the ears  74 ,  76 . 
         [0021]    The rightmost end of the cylinder  70  is also pivotally coupled to an upright ear  86  that is welded to the upper surface of the rectangular tube  32 . A hinge pin  88  pivotally joins the right end of the cylinder  70  to the ear  86 . The hydraulic actuator  72  is connected between the crossbar member  36  and the rectangular tube  32  in exactly the same manner and, thus, need not be described in detail. 
         [0022]    Those skilled in the art can appreciate that, because the stroke axis of the cylinders  70  and  72  are displaced from the pivot axis of the crossbar member defined by the hinge pin  88 , when the piston rods  80  and  81  of the cylinders  70  and  72 , respectively, are simultaneously retracted into their respective cylinders, the crossbar  36  with the teeth  38 - 48  will rotate clockwise when viewed as in  FIG. 1 . 
         [0023]    Referring next to  FIG. 2 , there is shown a longitudinal cross-section through the steel tubular arm  62  to which the crossbar member  36  is welded at one end and that is pivotally connected to the rectangular tube  32  through the clevis connection  66  with its hinge pin  68 . Contained within the hollow interior of the rectangular tube  62  is a further hydraulic cylinder  90  whose piston rod  91  extends through aligned bores formed through the opposed sidewalls of the crossbar member  36  and into a slide  59  to which the bracket  52  that is affixed to the tine  40  is connected. The opposite end of the cylinder is pivotally connected to the inner sidewall of the rectangular tube  32  by a clevis connection  68 , allowing the cylinder  90  to rotate with the outer arm  62 . A hydraulic connection to the cylinder  90  is made through a hose  94  and a conventional hose connector  96  that extends through the wall of the rectangular tube  62 . The tubular arm  64  also contains a hydraulic actuator configured in the same way as cylinder  90  of  FIG. 2 . 
         [0024]    Actuation of the cylinder  90  and its counterpart in arm  64  will cause reciprocal movement of the cylinder rods liked  91 . The stroke length thereof is approximately 8 inches. 
         [0025]    When used to remove silage from a conventional silage storage bag, the operator will approach the open end of the silage bag with the tines  38 - 48  elevated as in  FIG. 3  and will drive the scoop bucket  18  into the mass of silage at which point the hydraulic cylinders  70  and  72  will be actuated to swing the crossbar and tines into the mass of silage, thereby penetrating into a mass of silage sufficient to fill the scoop bucket. The operator will then attempt to maneuver the skid steer loader to empty the silage from the scoop bucket into a nearby truck or wagon (not shown) that will be used to carry the silage to the point where it is to be fed to the animals. Before too long, the ground surrounding the open end of the silage bag will become wet and slippery from the moist silage such that the wheels of the skid steer loader will often loose sufficient traction to allow the tines to be pulled free from the mass of silage and the vehicle becomes stuck. When this occurs, the operator can operate a control lever on a valve box in the cab to deliver hydraulic fluid under high pressure to the cylinders  90  contained within the steel tube arms  62  and  64  causing the two tines  40  and  46  to push out and away from the crossbar member  36  as in  FIG. 4 , so as to push against the silage mass with a force sufficient to overcome the retaining force acting against the remaining tines and effectively freeing the fixed tines and moving the skid steer loader vehicle rearward away from the mass of silage and thus obviating the need to use another vehicle to pull the skid steer loader and scoop bucket free from its stuck condition. 
         [0026]    The hydraulic system for the skid steer loader including its main hydraulic pump and the oil flow controller in the operator&#39;s cab are used to deliver hydraulic fluid to the lift cylinders  70  and  72  and to the push-out cylinders  90 . It has been found convenient to employ a sequence-type valve in the hydraulic circuit for the grapple arranged such that when the pressure applied to the cylinders  70  and  72  reach a predetermined setting, hydraulic oil flow is directed to the cylinders  90  to push out the tines  40  and  46 . For example, when the pressure forcing the piston rods  80  and  81  out reaches about 2,500 pounds, when typically only occurs when the tines  38  . . .  48  are no longer able to penetrate deeper into the silage mass, the sequence valve operates to direct hydraulic oil flow to the cylinders  90  allowing about 12 tons of force for pushing against the compacted mass of silage to thereby displace the work vehicle from a stuck position. 
         [0027]    Those skilled in the art can appreciate that while a sequence valve is well suited to the present invention, a separate electrically-operated valve may also be used to control hydraulic oil flow to the cylinders  90  once it is determined that the work vehicle has become mired. 
         [0028]    This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.