Abstract:
Disclosed is a grapple and boom assembly with power tilt mechanism that can be controlled into an engaged position to tilt the grapple relative to the boom. The tilt mechanisms use a push arm that is mounted on the boom at a joint, such as to pivot. A push arm actuator is joined to the push arm to power operation thereof by extension or contraction of the actuator. The push arm includes a movable contact element, such as a roller that bears upon a trackway mounted upon the grapple assembly below the main pivot. A second version is shown wherein two tilt mechanisms are included one below and one above to provide power tilt in either direction yet allow the grapple to be operated in a free suspension mode when desired.

Description:
TECHNICAL FIELD  
       [0001]     The invention relates to grapples that are mounted on booms and equipped for adjustable angular orientation of the grapple.  
       BACKGROUND OF THE INVENTION  
       [0002]     It has been found desirous to have power control of the angle of a grapple mounted on a boom. A typical application for grapples is in the timber industry where logs are picked up and moved. Due to the various slopes and roughness of the terrain, the grapple is more easily maneuvered and achieves better control if provided with a power pivot connection that allows the grapple to be angled for interaction with the load being engaged.  
         [0003]     Most prior art grapples having tilt angle control have the grapple fixed to the actuator. This configuration has disadvantages when the logs are being pulled because the forces developed may increase due to the tilt angle established by the actuator. Such configuration may cause mechanical failures of the grapple, boom or tilt actuator because of such incidentally increased forces. Free suspension of the grapple during such operations has advantages in performing machine operations and aids in reducing machine maintenance.  
         [0004]     Another problem associated with prior grapple arrangements are the size of the units. Many have extending parts which can impede operation, reduce visibility and cause potential safety risks to the operator or workers in the surrounding area. Extending parts may also become entangled in tree limbs and brush which may slow operations. Thus it is desirable to have a power is tilting grapple which has minimal extensions from the boom and grapple assembly and is compact and relatively light in weight.  
         [0005]     It is also important in equipment of this type to have components which are simple, reliable and strong. This allows the equipment to maintain operations despite adverse conditions and extended field operation assignments. Rugged parts not subject to failure are of particular advantage.  
         [0006]     In many log skidders, the boom is constructed using a boom having a singular member. However, greater flexibility of operation is provided by booms having two or more boom members that can be controlled independently. These multi-section booms often have close working spaces and this additionally requires compact arrangement of any tilting mechanism that may be employed.  
         [0007]     The majority of log skidders having booms and grapples do not have any ability to power tilt the grapple relative to the boom. These machines typically have some form of damping system to reduce free swinging of the grapple hung from its supporting grapple mounting joint. However, such damping systems (sometimes called “snubbers”) do nothing to provide controlled tilt positioning of the grapple. Thus, there is also a large need for a power tilt mechanism that can be easily retrofit onto existing booms and grapples to provide this improved operation and functionality. The numerous different designs of booms and grapples from different manufacturers, models and years causes difficulties in creating a one or a small number of designs that can be mounted upon a wide variety of machinery.  
         [0008]     One or more of these and other problems of the prior art are addressed by the invention described herein. Other advantages and benefits of the current invention will be apparent from the description given herein or may be first appreciated upon further use of the invention.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     Preferred embodiments of the invention are described below with reference to the following accompanying drawings.  
         [0010]      FIG. 1  is a side elevational view of a forestry tractor fitted with a boom and grapple assembly according to a preferred version of this invention.  
         [0011]      FIG. 2  is a side elevational view of the tractor of  FIG. 1  with the boom and grapple assembly adjusted so the grapple is in a tilted orientation.  
         [0012]      FIG. 3  is a side elevational view of selected portions of the boom and grapple assembly shown in  FIG. 1 . The grapple is shown in a freely suspended position relative to the main pivot.  
         [0013]      FIG. 4  is a side elevational view similar to  FIG. 3  with the grapple shown further tilted.  
         [0014]      FIG. 5  is a side elevational view similar to  FIGS. 3 and 4  with the grapple shown still further tilted and the boom extended.  
         [0015]      FIG. 6  is a perspective view showing the boom and grapple assembly of  FIG. 1  in a different position to illustrate additional features of the grapple.  
         [0016]      FIG. 7  is a schematic side elevational view of a second embodiment boom and grapple assembly fitted with power tilt mechanisms according to another version of the invention.  
         [0017]      FIG. 8  is a schematic side elevation view of the assembly shown in  FIG. 7  moved into a more inwardly tilted position.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0000]     Introductory Note  
         [0018]     The readers of this document should understand that the embodiments described herein may be defined by relying on terminology used in any section of this document and other terms readily apparent from the drawings and language common therefor. This document is premised upon using one or more terms with one embodiment that will in general apply to other embodiments for similar structures, functions, features and aspects of the invention. Wording used in the claims is also descriptive of the invention. Terminology used with one, some or all embodiments may be used for describing and defining the technology and exclusive rights associated herewith unless specifically indicated otherwise.  
         [0000]     Introduction and General Configuration  
         [0019]      FIG. 1  shows a preferred construction for a boomed grapple machine  10  made according to this invention. The boomed grapple machine  10  includes a vehicle  13 . Vehicle  13  is used to transport and facilitate use of a combined boom and grapple assembly  20  which is mounted thereon. The combined boom and grapple assembly  20  has a boom assembly portion  30  and a grapple assembly portion  40 .  
         [0020]     Vehicle  13  is preferably a tracked vehicle although wheeled or other types of vehicles may be suitable depending upon the terrain and particular use of the boom and grapple machine  10 .  
         [0000]     Boom Assembly  
         [0021]     The boom assembly  30  is used to support the grapple assembly  40  and to position it to the extent of the boom assembly&#39;s range of motion. As shown, boom assembly  30  has multiple boom members. The first or jib boom member  31  and a second or main boom member  32  is an exemplary construction although others are possible. The main boom member  32  is joined to the tractor or other vehicle  13  at boom mounting pivot  33 . A main boom operator is provided in the form of a linear actuator which is preferably a hydraulic ram or cylinder  35 . This actuator  35  contracts or extends to boom up or boom down the main boom member, attached jib member and grapple and tilt assemblies described further hereinafter.  
         [0022]     The jib boom member  31  is pivotally connected at jib pivot joint  37 . Joint  37  can be made using a variety of conventional bearings or future technology capable of such service. Jib  31  is pivoted using a jib operator in the form of another hydraulic ram  38 . Jib actuator  38  is extended to rotate the jib distal end down in a counterclockwise action as illustrated in  FIG. 1 . Jib actuator  38  is contracted to rotate the jib distal end up in a clockwise action as viewed in  FIG. 1 . The proximate end of the jib is connected to the jib actuator  38  in pivotal relationship thereto.  
         [0023]     The grapple assembly  40  is connected to the distal end of the jib at a main pivot joint  41 . Main pivot joint  41  defines a main pivot joint pivot axis which is parallel to the boom pivot axis or axes, such as the pivot axis of jib pivot joint  37  and the pivot axis for main boom pivot joint  33 . Main pivot joint  41  may be constructed according to a variety of shaft or bearing arrangements as are now available of hereafter developed. Main pivot joint  41  serves as the connection joint between the boom assembly  30  and the grapple assembly  40 .  
         [0000]     Grapple Assembly  
         [0024]      FIG. 6  shows the grapple assembly  40  well and should be referred to for the following discussion. The grapple assembly can be made according to a variety of conventional or future designs. Grapple assembly  40  is shown with two grapple tongs  48  which are supported by a grapple head  42  at tong pivot joints  43 . The grapple tongs may desirably be provided with stabilizer ribs  49  which preferably run to or near the pivot joints  43 .  
         [0025]     As shown, each grapple tong  48  has a tong operator  44  which is advantageously a hydraulic ram. The tong operating ram  44  is pivotally connected at a lower end to a tong operating shoulder  45  at lower mounting pivot  46 . The upper end of operator  44  is pivotally connected to the headpiece  42  at an upper tong operator connection joint  47 .  
         [0026]     The grapple assembly shown also includes a support linkage  50 . Support linkage  50  is connected at the upper end thereof to main pivot joint  41 . The support linkage has a linkage member  51  which connect to pivot joint  41 . The lower end of the support linkage may advantageously have a secondary pivot joint  52 . The pivot axis of secondary joint  52  is spaced from and preferably, orthogonal to the pivot axis of main joint  41 .  
         [0027]     Secondary joint  52  also preferably has a bottom mounting piece  53  which can be used to mount a swivel operator  54  or it can be formed as part of the swivel operator. The swivel operator is preferably a hydraulic operator that allows the grapple head  42  to pivot about a longitudinal grapple axis. The swivel operator may be limited to a range of motion or be continuously able to swivel in either direction. Hydraulic fluid or other power supply may be connected to the swiveling grapple sub-assembly using hydraulic lines  57 . Lines  57  run to the boom and are desirably routed inside the boom members for protection.  
         [0000]     Grapple Tilt Mechanism  
         [0028]      FIG. 6  and  FIGS. 3-5  show a preferred grapple tilt mechanism  70  made in accordance with the inventions. The grapple tilt mechanism  70  can be either provided during original manufacture or added as a retrofit kit installed on a machine similar to machine  10  but without the grapple tilt mechanism. As shown, the grapple tilt mechanism  70  includes at least one mounting bracket, such as boom mounting bracket  71 . Boom mounting bracket  71  may be installed by welding to the jib or other boom member to which it is attached.  
         [0029]     Mounting bracket  71  includes at least one joint for connection of parts thereto. A push arm or first joint  72  is advantageously provided for joinder of a push arm  73 . Push arm joint  72  is preferably a pivotal joint, such as those commonly used in heavy equipment for pivoting parts powered by hydraulics.  
         [0030]     The mounting bracket  71  also preferably includes a second or actuator connection joint  75  used to mount one end of a hydraulic ram  76  or other suitable power actuator. The actuator  76  also is joined with the push arm  73  using at least one push arm actuator joint  77 . Joint  77  is advantageously a pivotal joint.  
         [0031]     Extension of the push arm actuator  76  causes the distal end of the push arm to extend outwardly and toward the grapple is assembly. Contraction of the push arm actuator  76  causes the distal end of the push arm to retract inwardly and away from the grapple assembly.  
         [0032]     The push arm  73  is also provided with a movable contact element  78  which is preferably provided in the form of a rocking, swiveling or more preferably a rolling element, such as a roller wheel or wheels, as shown. The contact element is mounted to the push arm at a contact element joint  79  which in the case of the illustrated construction is a pivot joint  79 . The construction may include one contact element or several as needed.  
         [0033]     The grapple tilt mechanism includes the boom assembly mounted portions described above, and also includes a grapple assembly mounted portions. As shown, the grapple mounted portion is in the form of an elongated trackway or contact plate that is connected to the grapple linkage  50  at a suitable position for engagement by the contact element, such as roller  78 . The particular shape of the trackway is variable depedent upon the action and path of the contact element as it engages and moves along the trackway  80 . With regard to the construction illustrated, the trackway  80  is welded or bolted to the inboard side of the grapple linkage  50  in proximity to the underboom mounting of the boom portions of the tilt mechanism assembly.  
         [0034]     The operation of actuator  76  is preferably accomplished using hydraulic fluid pressurized and supplied through actuator supply lines (not shown). This is done in the convention fashion and control is provided by control valves (not shown) which appropriately supply pressurized fluid to the hydraulic ram to cause extension or contraction as is desired. This is preferably constructed so that actuator  76  has its own independent control valves for independent operation.  
         [0000]     Operation &amp; Method for Tilting Grapple Outwardly  
         [0035]      FIGS. 3-5  show different boom and grapple assembly i, positions and orientations in a schematic manner. Many elements have been removed for simplicity of illustration and understanding, particularly the lower portions of the grapple assembly are shown disconnected at the secondary joint  52 .  
         [0036]      FIG. 3  shows the boom in an extended position with both the main and jib sections extended. The grapple connection link  50  hangs vertically in free suspension from main pivot joint  41 . Roller  78  on the push arm is not engaging the trackway piece  80 . The grapple linkage is free to swing rearwardly and to a slight degree forwardly in response to forces applied by any load, such as a group of logs as pictured in  FIG. 1  or  2 .  
         [0037]      FIG. 4  shows the boom assembly in a forward and contracted position with the jib close to the main boom and the main boom retracted into an upstanding position. Additionally the hydraulic control valves (not shown) controlling flow of hydraulic fluid to the push arm actuator  76  have been controlled to extend the actuator and pivot the contact member  78  into engagement with the trackway  80  and force the grapple assembly to tilt backwardly about main pivot  41 . As this is done the contact member, such as roller  78 , rolls or otherwise moves across the trackway  80 .  
         [0038]      FIG. 5  shows the grapple extended using the tilt mechanism with the boom assembly now moved to an extended position. This allows further tilt of the grapple and extends the grapple further from the vehicle to which it is attached.  
         [0039]     The steps of the novel methods may include extending a push arm mounted upon the boom assembly for movement using a power actuator. The methods may further include engaging a roller or other movable contact member or members against a trackway mounted on the grapple assembly. The methods further preferably include moving the movable contact member upon or across the trackway, such as by rolling a roller contact member or members against the trackway by further extending the push arm using the push arm actuator. The resulting tilting of the grapple assembly relative to the boom assembly by said further extending allows the grapple to be repositioned and reoriented into a more tilted position.  
         [0000]     Operation and Method for Retracting Tilted Grapple Inwardly  
         [0040]     The retraction of tilt mechanism  70  is the reverse of the extension operation explained above. It involves contracting the actuator  76  which causes retracting of the distal end of the push arm  73 . Depending upon the initial or starting position of such retraction, the contact element  78  moves, such as rolls downwardly upon the trackway and at a release angle the contact element separates from the trackway to allow free suspension of the grapple assembly.  
       Alternative Embodiment  
       [0041]      FIGS. 7 and 8  show another possible construction according to the inventions hereof. The construction includes all features described hereinabove and the same reference numerals are used to indicate such features. Description is given above and need not be repeated here.  
         [0042]     The construction shown in  FIGS. 7 and 8  differs from that of the other figures in that the boom assembly has two opposing tilt mechanisms installed thereon. The first or underside tilt mechanism  70  is described above. The second or overside tilt mechanism  170  is similar to tilt mechanism  70  except it is mounted using two mounting brackets  171  and  171 ′ that are independently welded to the boom assembly.  
         [0043]     Other parts of the second tilt mechanism are similar to those of the first tilt mechanism and are indicated using the same numbers with a leading  100 , e.g. actuator  176  versus actuator  76 .  
         [0044]     The operation of the second tilt mechanism is similar to that of the first tilt mechanism except the trackway is forced inwardly by extension of the actuator  176  and counterclockwise pivotal movement of the push arm  173 . The particular shape of the push arm  173  may be varied dependent upon the amount of spacing desired for rearward tilting of the grapple assembly without contact. Retraction of the second tilt mechanism occurs by contraction of actuator  176  which causes push arm  173  to pivot about central pivot joint in a clockwise movement as shown in  FIG. 7 .  
         [0000]     Interpretation Note  
         [0045]     The invention has been described in language directed to the current embodiments shown and described with regard to various structural and methodological features. The scope of protection as defined by the claims is not intended to be necessarily limited to the specific features shown and described because other forms and equivalents for implementing the invention can be made and in some cases this is done simple to evade the intended purpose of this