Abstract:
In a shaker head for a tree shaker, a hydraulically actuated ram is mounted between the clamping arm and frame of the shaker head with a pin assembly which extends into a spherical bearing disposed within an aperture of the shaker head. The spherical bearing allows a certain amount of misalignment and provides a through-hardened and lubricated wear point which prevents or reduces structural failure in the shaker head components.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates generally to tree shakers for harvesting nuts, fruits, and other tree-borne crops, and more specifically to an improved tree shaker head having an improved assembly for attaching a hydraulically actuated ram within the shaker head. 
         [0002]    Tree shakers are known in the art for harvesting nuts, fruits, and other tree-borne products. Shakers typically employ a boom extending forwardly from a tractor or other device, with a shaker head present at the end of the boom for grasping a tree and imparting a shaking force to the tree. The shaker head is positioned around a tree and when the hydraulically actuated ram on the clamp cylinder is energized, pads on the inside of the shaker head compress and conform round the trunk, while subtly twisting the shaker head into alignment. The hydraulic system then sequences from the clamping circuit to the shaking circuit, launching the shaker head into a vigorous shaking pattern during which the crop of fruit or nuts rains down in a cloud of dust and debris. When the shake control is released dynamic braking is applied and the shaker head brakes hard to a stop. The shaker head is then unclamped and the unit moves onto another tree. This process is repeated, often several times a minute depending upon the tree spacing and operator, until all trees in the orchard have been shaken. The shaking action of the device dislodges fruits, nuts, and other products, which then fall from the branches of the tree to be harvested. The shaking action is aggressive, with severe loads imparted to various components of the device, particularly within the shaker head. 
         [0003]    The commonly used tree shaker comprises a frame having a hollow welded steel case structure containing the drive sheave, drive belt, two or more eccentric rotating masses, one or more hydraulically actuated rams and hydraulic hose routings. A hydraulic motor typically mounts within or on the top of the case structure and is connected to a drive pulley. A stationary arm is integral to or affixed to the frame. Opposing the stationary arm is a clamping arm which is attached to the rear of the frame by a pivot pin. The clamping arm applies a compressive force during the shaking process when a hydraulically actuated ram is actuated, causing the clamp arm to pivot about the pivot pin and move toward the stationary arm, causing the clamping arm and stationary arm to close about a tree trunk. Once the arms of the head are closed about the tree trunk, vibration is initiated within the shaker head. Typically the shakers use stacked counter rotating eccentric mass energy wheels to generate the vibration or pulse, which is created by the rotation of an eccentric mass about a fixed common shaft. Once the shaking cycle is finished, a hydraulically actuated ram causes the clamping arm to open with respect to the stationary arm. 
         [0004]    It is to be appreciated that the various components of the shaker head are subjected to significant loading during the shaking cycle of the above described process, which is repeated almost immediately and repeatedly, but each time all components of the shaker head are twisted into alignment. As a result of this repeated sequence, various shaker head components are continually stressed and subject to wear and failure. The inventor herein has found that some of the most common wear and failure points in existing shaker heads are the end connectors of the hydraulically actuated ram(s) utilized to open and close the clamping arm with respect to the stationary arm, and the structural components of the shaker head to which the end connectors of the hydraulically actuated ram(s) are attached. The end connectors utilized for attaching the hydraulically actuated ram(s) to the clamping arm are typically a clevis type connector as shown in  FIG. 2  which is attached to an attachment point on the shaker on the frame or the clamping arm by a pin. Because of the inevitable misalignment of the clamping arm with the stationary arm as the head repeatedly engages trees, followed by the significant loads imposed on these joints as the shaker is engaged, all components of the hydraulically actuated ram and related attachment structures of the shaker head are subject to failure. These failures are expensive to repair and failure typically results in a shaker being idled during the critical harvesting season. 
       SUMMARY OF THE INVENTION 
       [0005]    Embodiments of the present invention address the problem identified above. There are a variety of different tree shakers which are utilized for harvesting crops from trees, but each of the shakers generally utilizes one or more hydraulically actuated rams to close the shaker head about the tree trunk. The present invention provides a spherical bearing (sometimes referred to as a spherical-radial bearing) on one or both ends of the hydraulically actuated ram, where the spherical bearings allow a certain amount of misalignment and which provide a through-hardened and lubricated wear point which prevents or reduces structural failure in the shaker head components including, but not limited to, pins and pin bosses. The spherical bearings are relatively easy to replace and allow a machine to be expeditiously repaired if a spherical bearing is worn. 
         [0006]    Embodiments of the present invention may be utilized in a shaker head of the type having a frame having case structure which generally contains a drive sheave, a drive belt, at least one eccentric rotating mass, a hydraulic motor mounted within or on the case structure, a stationary arm integral to the frame or affixed to the frame, and a clamping arm in opposite relation to the stationary arm. The clamping arm, which may also have a case structure, is pivotally attached to the frame. A hydraulically actuated ram is connected between the frame and the clamping arm, where the operation of the hydraulically actuated ram causes the clamping arm to open and close with respect to the stationary arm, thereby providing the clamping force for locking the shaker head around a tree trunk. The hydraulically actuated ram comprises a cylinder housing and a piston slidingly disposed within the cylinder housing. 
         [0007]    Embodiments of the present invention provide an attachment assembly for attaching either end of the hydraulically actuated ram to the shaker head. It is to be appreciated that the present invention may be utilized for attaching either a single end or both ends of the hydraulically actuated ram to the shaker head. 
         [0008]    Components of the attachment assembly include a first end of the cylinder housing of the hydraulically actuated ram which end may be integral to the housing, where the first end has a first aperture. Similarly, the piston portion of the hydraulically actuated ram may have a second end which may be integral to the piston, where the second end has a second aperture. A first spherical bearing may be disposed within the first aperture and, optionally, a second spherical bearing may be disposed in the second aperture. A first pin assembly attaches the first end of the cylinder housing to a first attachment aperture in either the clamping arm or the frame, where the first attachment aperture may extend through the entire case structure, with a boss on either side of the first attachment aperture. The first pin assembly is made up of a first male member having which has external threads and a first sleeve member which has internal threads, where the first male member makes up to the first sleeve member, typically fully making up to one another such that the threads of the male member are fully made up within the first sleeve member. The first male member may have a head which may abut a first boss on the case structure The first sleeve member may also have a head which abuts a second boss on the case structure. 
         [0009]    The first pin assembly may be disposed within the first attachment aperture such that the first sleeve is inserted through the first spherical bearing. A second pin assembly may be used to attach the second end integral to the piston to a second attachment aperture in the frame or the clamping arm. The second pin assembly is made up of a second male member having external threads and a second sleeve member having internal threads. The second pin assembly is disposed within the second attachment aperture such that the second sleeve is inserted through the second spherical bearing. 
         [0010]    Embodiments of the attachment assembly for a shaker head actuator provides for the wear points to be concentrated within the hardened spherical bearing and the hardened sleeve which surrounds each of the pins. Further structural elements of the invention may include structural reinforcement, such as bosses, at the attachment apertures in the clamping arm and the frame. A spherical bearing may be inserted within the first aperture of the hydraulically actuated ram and the first end of the cylinder housing inserted between opposing plates in the clamping arm, where a top spacer may be placed between the top plate of the clamping arm and the spherical bearing, a bottom spacer may be placed between the spherical bearing and the bottom plate of the clamping arm. When the pin assembly is installed, the first male member is made up into the threads of the first sleeve member, where making up the first male member preloads the spherical bearing within the first aperture. Likewise, installation of the second pin assembly preloads the spherical bearing within the second aperture. The purpose of the preload is to eliminate movement and vibration in both the axial and radial directions, eliminating undesirable wear in all related components. 
         [0011]    The spherical bearing may have a hardened outer ring, a hardened inner ring and one or more lubrication ports. The inventor herein has found that an inner diameter of 2½ inches for the spherical bearing, where the pin assembly sleeve has an outside diameter in accord with the bearing diameter, provides acceptable service. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  depicts a prior art shaker head. 
           [0013]      FIG. 2  shows how the piston end of a hydraulically actuated ram is installed in the prior art shaker head of  FIG. 1 . 
           [0014]      FIG. 3  depicts a shaker head which incorporates an embodiment of the attachment assembly of the present invention for attaching an end of a hydraulically actuated ram within a shaker head. 
           [0015]      FIG. 4  shows a close up of the attachment assembly of the present invention utilized on the cylinder end of a hydraulically actuated ram. 
           [0016]      FIG. 5  depicts an attachment point in the case structure for an end of a hydraulically actuated ram. 
           [0017]      FIG. 6  shows a close up of the piston end of the hydraulically actuated ram which utilizes the same type of attachment assembly as for the cylinder end depicted in  FIG. 4 . 
           [0018]      FIG. 7  shows a hydraulically actuated ram of the present invention showing the first aperture and second aperture of the ram, with a spherical bearing inserted within each aperture. 
           [0019]      FIG. 8  shows an exploded view depicting the relative positions of the fastener assembly, spacer plates and spherical bearing when installed with a hydraulically actuated ram (not shown) to a shaker head. 
           [0020]      FIG. 9  depicts a spherical bearing which may be utilized in embodiments of the present invention. 
           [0021]      FIG. 10  depicts a pin assembly which may be utilized in embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    In the present disclosure, terms designating orientation, direction, or relative position, such as the terms upper, lower, top, bottom, inward, outward, right, left, etc., are made with respect to orientations, directions, and relative positions as indicated in the Figures herein. However, such terms are utilized herein with respect to the drawings only, and such terms do not limit the application of embodiments of the invention as actually utilized. 
         [0023]    Referring now to the figures,  FIG. 1  depicts a prior art shaker head  100  as generally utilized for shaking trees to drop the crop to the ground. The embodiment of  FIG. 1  shows an embodiment in which two hydraulically actuated rams  104 ,  120  are utilized to open and close the clamping arm  106  with respect to the stationary arm  116 . Hydraulically actuated ram  104  is utilized to close the clamping arm while hydraulically actuated ram  120  pulls chain  122  which pulls the clamping arm away from stationary arm  116  to open the shaker head  100 . 
         [0024]      FIG. 2  shows a typical prior art structure for attaching the components of a hydraulically actuated ram  104  to a shaker head. In this example, piston  102  of hydraulically actuated ram  104  is attached to the clamping arm  106  by a clevis  108  on the piston with pin  110  inserted through the clevis  108  and through an ear member  112  on the clamping arm  106 . In this embodiment, the retraction of piston  102  into hydraulically actuated ram  104  operates to close the clamping arm  106  toward the stationary arm  116 . In this type connection, among other shaker head components, pin  110 , clevis  108  and ear member  112  are subjected to significant loads as the hydraulically actuated ram  104  maintains the shaker head in the closed position about a tree trunk during the shaking operation. This configuration typically results in wear and potentially failure in each of these components. 
         [0025]      FIG. 3  depicts a shaker head  10  equipped with an embodiment of the present attachment assembly for the hydraulically actuated ram of the shaker head. In this embodiment, a single hydraulically actuated ram  24  is required to open and close the shaker head as compared to the shaker head  100  depicted in  FIGS. 1 and 2 . 
         [0026]    For embodiments of the present invention, the shaker head  10  has a frame  12 . The shaker head  10  has a stationary arm  18  which typically is an integral component of the frame  12  with the stationary arm  18  extending outwardly from the front of the frame. Shaker head  10  also has a clamping arm  20  which is pivotally attached by a pivot pin  22  to frame  12 . Frame  12  and clamping arm  20  typically each have a case structure comprising a top plate  14  and a bottom plate  16 . 
         [0027]    Other internal components of the shaker head, such as a hydraulic motor, drive sheave, drive belts, eccentric rotating weights and other components, which are not shown, will typically be contained in the space between top plate  14  and bottom plate  16 . Structural support members, such as vertical plate  50 , will connect top plate  14  and bottom plate  16 . 
         [0028]    A hydraulically actuated ram  24  connects frame  12  to clamping arm  20 . For the embodiment shown in  FIG. 3 , the hydraulically actuated ram  24  is disposed between top plate  14  and bottom plate  16  of clamping arm  20  toward the front of the shaker head  10 , i.e., the end of the shaker head having the clamping arm  20  and the stationary arm  18 . The hydraulically actuated ram  24  has a cylinder housing  26  and a piston  28  which extends and retracts as hydraulic pressure is applied to the ram. It is to be appreciated that for this embodiment of the shaker head  10 , a single hydraulically actuated ram  24  is required to open and close the clamping arm  20  with respect to the stationary arm  18  as compared to the prior art shaker head shown in  FIGS. 1-2  which requires two hydraulically actuated rams  104 ,  120 . 
         [0029]    The hydraulically actuated ram  24  may have an end  30  integral to the cylinder housing  26  where end  30  is connected to an attachment point  32  of the clamping arm  20 . The hydraulically actuated ram  24  may also have an end  34  which is attached to piston  28  where end  34  is connected to an attachment point  36  in frame  12 . The attachment points  32 ,  36  typically comprise apertures  52  through the case structure of frame  12  and clamping arm  20 . Apertures  52  may be reinforced with bosses  54  projecting from the plates through which the apertures  52  extend. 
         [0030]    End  30  of cylinder housing  26  has an aperture  38  into which a spherical bearing  40  may be placed. The spherical bearing comprises a hardened outer ring  42  and a hardened inner ring  44 , which floats within the outer ring and allows tilt (i.e., self-aligning) movement of the inner ring with respect to the outer ring as indicated in  FIG. 9 . Similarly, end  34 , which is attached to piston  28 , has an aperture  46  into which a spherical bearing  40  may also be placed. As indicated above, embodiments of the present invention may be utilized to attach both ends of the hydraulically actuated ram  24  between the frame  12  and the clamping arm  20 , or for attaching a single end of the ram to either the frame or clamping arm. 
         [0031]      FIGS. 4 and 5  show close-up views of attachment point  32  in the clamping arm  20 . As further shown in  FIG. 8 , attachment point  32  may have opposite facing apertures  52  placed within top plate  14  and a bottom plate  16 . The apertures  52  may comprise a boss  54  projecting from either side of top plate  14  and bottom plate  16  to provide additional structural strength. The configuration of attachment point  36  may be the same as that described above for attachment point  32 . 
         [0032]    As depicted in the exploded view of  FIG. 8 , a pin assembly  60  attaches each end of the hydraulically actuated ram  24  to attachment points  32 ,  36 . Spacers  70  may be placed on either side of spherical bearing  40 . Spherical bearing  40  may also have a lubrication port  72 . 
         [0033]    An embodiment of pin assembly  60  is depicted in detail in  FIG. 10 . Pin assembly  60  may have a male member  62  having external threads  64  and head  74  Pin assembly  60  may further have a sleeve member  66  where the sleeve member has internal threads  68  and sleeve head  76 . When installed, a separate pin assembly  60  may be inserted within the apertures  52  at each of the attachment points  32  and  36  such that the pin assembly is inserted through the spherical bearing  40  within each end of the hydraulically actuated ram  24 , with the sleeve member  66  immediately adjacent to the inner ring  44  of the spherical bearing. It is to be appreciated that when the pin assembly is installed substantial torque may be applied without imposing any binding on spherical bearing  40  because of the configuration of the pin assembly  60  and bosses  54 . With this configuration, the pin assemblies  60  connecting the respective ends of hydraulically actuated ram  24  to the attachment points  32 ,  36  may float or tilt during the shaking operation without wear in the attachment points and related structure. 
         [0034]    Having thus described the invention, what is claimed as new and desired to be protected by Letters Patent includes the following: