Abstract:
A positioning system, attachable to a vehicle for remote operation of the chain saw by a user sitting in the vehicle. A shock absorber indicator functions to tell the user when the weight on the limb is appropriate to engage the saw, and additionally cushions the drop when the saw cuts through the limb.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE STATEMENT 
       [0001]    This application claims priority to provisional U.S. Application No. 62/291,825 filed Feb. 5, 2016. This application is also a continuation-in-part of U.S. application Ser. No. 13/398,465 filed Feb. 16, 2012 which is a divisional of U.S. application Ser. No. 11/827,485 filed Jul. 11, 2007, now abandoned. Each of the above-referenced patent applications is hereby expressly incorporated herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTIVE CONCEPTS 
       [0002]    1. Field of the Inventive Concepts 
         [0003]    The inventive concepts disclosed and claimed herein relate to a positioning system, and more particularly, but not by way of limitation, to a positioning system attachable to a vehicle for remote operation of a saw at elevated positions by a user sitting in the vehicle. 
         [0004]    2. Brief Description of Related Art 
         [0005]    Tree limbs are typically removed by sawing, but many limbs are located higher than a person can reach standing on the ground. Those limbs that can be reached are typically directly overhead of the worker and pose significant danger when they fall. A lift or a tractor bucket can hold a worker aloft to use a hand-held saw to remove the target limb. But this procedure is also dangerous and usually requires two workers. Sometimes a worker uses a ladder or climbs the tree and pulls a chain saw up by a rope. However, the use of a power saw of any kind from a perch in a tree is fraught with dangers. 
         [0006]    Improvements are needed to enable a person to safely cut large tree limbs that are unreachable from the ground or that are directly overhead of the person. It is to such improvements, systems, and methods of making and using the same that the inventive concepts disclosed herein are directed. 
       SUMMARY OF THE INVENTIVE CONCEPTS 
       [0007]    The inventive concepts disclosed and claimed herein generally relate to a 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more implementations described herein and, together with the description, explain these implementations. The drawings are not intended to be drawn to scale, and certain features and certain views of the figures may be shown exaggerated, to scale or in schematic in the interest of clarity and conciseness. Not every component may be labeled in every drawing. Like reference numerals in the figures may represent and refer to the same or similar element or function. In the drawings: 
           [0009]      FIG. 1  shows the positioning system according to the present invention attached to a dirt bucket on a farm tractor wherein a hydraulically powered chain saw is attached to an upper arm. 
           [0010]      FIG. 2A  is a view of the positioning system shown in  FIG. 1  removed from the farm tractor. 
           [0011]      FIG. 2B  shows another positioning system embodiment including a limit strap. 
           [0012]      FIG. 3A  shows another positioning system embodiment including an indicating shock absorber. 
           [0013]      FIG. 3B  shows the positioning system of  FIG. 3A  indicating it is time to engage the saw. 
           [0014]      FIG. 3C  shows the inner working of the indicating shock absorber embodiment positioned as in  FIG. 3A . 
           [0015]      FIG. 3D  shows the inner working of the indicating shock absorber embodiment positioned as in  FIG. 3B . 
           [0016]      FIG. 3E  is a top sectional view of an indicating shock absorber embodiment positioned as in  FIG. 3A . 
           [0017]      FIG. 3F  is a top sectional view of an indicating shock absorber embodiment positioned as in  FIG. 3B . 
           [0018]      FIG. 3G  shows a positioning system embodiment having an indicating shock absorber on the arm side of the mast. 
           [0019]      FIG. 3H  shows the positioning system of  FIG. 3G  indicating it is time to engage the saw. 
           [0020]      FIG. 4  is another view of the positioning system shown in  FIG. 1 . 
           [0021]      FIG. 5  shows another positioning system according to the present invention wherein the telescoping mast is power operated. 
           [0022]      FIG. 6  is a view of the upper arm of the positioning system shown in  FIGS. 1, 2, and 4  wherein a portion of the upper arm is cut away to show a chain oil (sometimes also called bar and blade oil) reservoir. 
           [0023]      FIG. 7  is another view of the positioning system shown in  FIGS. 1-6  wherein the upper arm is folded alongside the telescoping mast for storage and transport. 
           [0024]      FIG. 8  is an enlarged detail of another positioning system according to applicant&#39;s invention. 
           [0025]      FIG. 9  is a view of another positioning system according to the present invention wherein the chain saw blade is generally aligned with the upper arm. 
           [0026]      FIG. 10  is an exploded view showing the hydraulically powered chain saw assembly shown in  FIGS. 1-9 . 
           [0027]      FIG. 11  is an enlarged view of a spacer block with oiling grooves. 
           [0028]      FIG. 12  shows another positioning system according to the present invention wherein the upper arm contains an automatic oiler for oiling the chain saw attached to the upper arm. 
           [0029]      FIG. 13  is another view of the positioning system shown in  FIG. 12 . 
           [0030]      FIG. 14  is a detailed enlarged view of the automatic oiler shown in  FIGS. 12-13 . 
           [0031]      FIG. 15  is another view of the automatic oiler shown in  FIGS. 12-14 . 
           [0032]      FIG. 16  shows another upper arm assembly according to the present invention wherein the hydraulically powered chain saw swings laterally from the end of the upper arm. 
           [0033]      FIG. 17  shows a nozzle mounted on the end of the upper arm for elevated treatment of trees utilizing pesticides, herbicides, air, or compressed gas. 
           [0034]      FIG. 18  shows another positioning system according to the present invention wherein a four-point linkage is attached to the bottom of a tractor&#39;s dirt bucket. 
           [0035]      FIG. 19  is another view of the positioning system shown in  FIG. 18  with the side of the dirt bucket cut away to show attachment of the telescoping mast to four-point linkage. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    Before explaining at least one embodiment of the presently disclosed inventive concept(s) in detail, it is to be understood that the presently disclosed inventive concept(s) is not limited in its application to the details of construction and the arrangement of the components or steps or methodologies set forth in the following description or illustrated in the drawings. The presently disclosed inventive concept(s) is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. 
         [0037]    Unless otherwise defined herein, technical terms used in connection with the presently disclosed inventive concept(s) shall have the meanings that are commonly understood by those of ordinary skill in the art. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. 
         [0038]    All of the articles and/or methods disclosed herein can be made and executed without undue experimentation in light of the present disclosure. While the articles and methods of the presently disclosed inventive concept(s) have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the articles and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit, and scope of the presently disclosed inventive concept(s). All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the presently disclosed inventive concept(s). 
         [0039]    As utilized in accordance with the present disclosure, the following terms, unless otherwise indicated, shall be understood to have the following meanings: 
         [0040]    The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one”, but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or that the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.” Throughout this application, the term “about” is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine the value, or the variation that exists among the study subjects. For example, but not by way of limitation, when the term “about” is utilized, the designated value may vary by plus or minus twelve percent, or eleven percent, or ten percent, or nine percent, or eight percent, or seven percent, or six percent, or five percent, or four percent, or three percent, or two percent, or one percent. The use of the term at least one of X, Y, and Z″ will be understood to include X alone, Y alone, and Z alone, as well as any combination of X, Y, and Z. The use of ordinal number terminology (i.e., “first,” “second,” “third,” “fourth,” etc.) is solely for the purpose of differentiating between two or more items and is not meant to imply any sequence or order or importance to one item over another or any order of addition, for example. 
         [0041]    As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. 
         [0042]    The term “or combinations thereof” as used herein refers to all permutations and combinations of the listed items preceding the term. For example, “A, B, C, or combinations thereof” is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, AAB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context. 
         [0043]    As used herein, the term “substantially” means that the subsequently described event or circumstance completely occurs or that the subsequently described event or circumstance occurs to a great extent or degree. For example, when associated with a particular event or circumstance, the term “substantially” means that the subsequently described event or circumstance occurs at least 80% of the time, or at least 85% of the time, or at least 90% of the time, or at least 95% of the time. The term “substantially adjacent” may mean that two items are 100% adjacent to one another, or that the two items are within close proximity to one another but not 100% adjacent to one another, or that a portion of one of the two items is not 100% adjacent to the other item but is within close proximity to the other item. 
         [0044]    The term “associate” as used herein will be understood to refer to the direct or indirect connection of two or more items. 
         [0045]    Turning now to the presently disclosed inventive concept(s), certain embodiments thereof are directed to a positioning system for elevated operation of a tree saw and other tools by a single operator who can remain in the seat of a vehicle such as a tractor, backhoe, skid loader, pickup, ATV, and the like. 
         [0046]    Referring generally to the drawings and more particularly to  FIG. 1 , a positioning system  50  with an attached hydraulic chain saw includes a mast  52  attached to the dirt bucket B of a tractor T and an upper arm  54  supported by the mast  52 . The mast  52  has a lower end portion  56  and an upper end portion  58 . The upper arm has a proximate end  60  and a distal end  62 . The proximate end  60  of the upper arm is pivotally attached to the upper end portion  58  of the mast  52 . A mounting plate  64  attached to the distal end  62  of the upper arm  54  by bolts  63 ,  65  (See  FIG. 2A ) supports a chain saw assembly  66 . Thus the tractor operator can position the tractor T beneath a tree and raise or lower the dirt bucket B of the tractor T to adjust the height of the chain saw assembly  66  with respect to a tree limb L selected for pruning or removal. 
         [0047]    Referring now to  FIGS. 2A, 2B, and 4 , in one embodiment the mast  52  is telescoping and consists of an outer mounting member  68  and a slidably extending inner member  70 . The outer mounting member  68  has bores  72 ,  74  for attachment to the side of the dirt bucket B of the tractor T using suitable bolts (not shown). A locking pin bore  76  is aligned with a selected bore  88  of spaced bores  78 ,  80 ,  82 ,  86 ,  88 ,  90  in the slidably extending inner member  70 . A locking pin  92  extends through the locking pin bore  76  in the outer mounting member  68  and the spaced bore  88  in the slidably extending inner member  70 . Thus the telescoping mast  52  provides a second point of adjustment of the height of the chain saw assembly  66  above the tractor T, thereby increasing the elevation at which the chain saw assembly  66  can be used to prune or remove tree limbs. 
         [0048]    Still referring to  FIGS. 2 and 4 , a pivot bracket  94  rigidly attached to the proximate end  60  of the upper arm  54  is pivotally attached to the upper end portion  58  of the mast  52  by a pivot bolt  96 . A mounting bracket  98  attached to the slidably extending inner member  70  receives one end of a hydraulic cylinder  100 . The other end of the hydraulic cylinder  100  is attached to a bolt  102  extending through the bracket  94 . Hydraulic lines  104 ,  106  (See  FIG. 5 ) provide control for the hydraulic cylinder  100 , so the operator&#39;s extension/retraction of the hydraulic cylinder along arrow  108  causes movement of the chain saw assembly  66  along arrow  110 . 
         [0049]    Still referring to  FIGS. 2 and 4 , the mounting plate  64  attached to the distal end  62  of the upper arm  54  supports the chain saw assembly  66 . A chain saw sprocket drive  112  driven by a shaft  114  from a hydraulic motor  116  (See  FIG. 4 ) is aligned with a standard chain saw blade  118  (sometimes also referred to as the chain saw bar) having elongated slots  120 ,  122  (See  FIGS. 10-11 ) for tension adjustment. A chain  124  engages the chain saw sprocket drive  112 . The position of the chain saw blade  118  with respect to the sprocket drive  112  determines the tension on the chain  124 . Bolts  126 ,  128  extending through bores  130 ,  132  in a chain saw blade locking plate  134 , through the elongated slots  120 ,  122  in the chain saw blade  118 , and through bores  136 ,  138  in the mounting plate  64  (See  FIGS. 10-11 ) are secured by nuts  140 ,  142  (See  FIGS. 10-11 ). Hydraulic lines  144 ,  146  connect the hydraulic motor  116  to a hydraulic power source (not shown) on the tractor T. An oil line  148  provides gravity feed of oil from an oil reservoir (See  FIG. 6 ) to the chain  124 . 
         [0050]    Referring now to  FIG. 2B , another positioning system  150  according to the present invention includes a limit strap  152  connecting the mounting bracket  98  and the bolt  102  in the pivot bracket  94 . The limit strap  152  permits limited movement of the bolt  102  with respect to the mounting bracket  98  along arrow  154 , thereby permitting the chain saw assembly  66  to move upwardly along arrow  156  in response to resistance from the targeted limb while preventing the chain saw assembly  66  from dropping downwardly along arrow  156  past a position wherein the chain saw assembly  66  cannot be used. 
         [0051]    It will be understood by one skilled in the art that a chain saw works best when the weight of the chain saw provides most of the force for making the cut in the target limb L. It will be further understood by one skilled in the art that the chain saw assembly  66  shown in  FIG. 2B  relies on the weight of the chain saw assembly  66 , whereas the hydraulic cylinder  108  shown in  FIG. 2A  permits the operator to apply a slight downward force to the chain saw assembly  66  during the cutting process. 
         [0052]    In one embodiment, as shown in  FIG. 3A  and  FIG. 3B , the positioning system  50 , attachable to a vehicle, for example a loader attachment on a tractor, for remote operation of the chain saw  66  by a user sitting in the vehicle, includes the mast  52 , the upper arm  54 , and a shock absorber  900 . The upper arm  54  has a proximal end  902  connected to the pivot bracket  94 , and a distal end  904  attached to the chain saw  66 . The pivot bracket  94  is pivotally connected to an upper portion  906  of the mast  52 . The upper arm  54  and the mast  52  form an angle  908  therebetween. The shock absorber  900  includes a casing  910  and a rod  912  extendable therethrough, the shock absorber  900  being pivotally connectable to the pivot bracket  94  at an upper portion  914  of the shock absorber  900 , and pivotally connectable to the mast  52  at a lower portion  916  of the shock absorber  900 . When connected, the shock absorber  900  determines a minimum angle  908 ′ between the upper arm  54  and the mast  52 . The rod  912  has an indicating portion  918  that extends from the casing  910  when the angle  908  between the upper arm  54  and the mast  52  is greater than the minimum angle  908 ′. 
         [0053]    In one embodiment shown in  FIG. 3C  and  FIG. 3D , the shock absorber  900  includes a coil spring  920 , a piston  922 , and a rebound stop  924 . Before the chain saw assembly  66  contacts the tree limb, as in  FIG. 3A , the indicating portion  918  of the rod  912  is pulled into the casing  910  as shown in  FIG. 3C  by the weight of the chain saw assembly  66 . Once the chain saw assembly  66  contacts the tree limb as in  FIG. 3B , and the weight of the chain saw assembly  66  becomes at least partially supported by the tree limb, the rod indicating portion  918  is pulled outward from the casing  910  (see  FIG. 3D ). An appropriate length of the indicating portion  918  becoming visible to the operator lets the operator know that the required amount of weight is on the limb and it is time to engage the saw. The functioning of the indicating portion  918  can also be understood from  FIG. 3E  and  FIG. 3F . 
         [0054]    The rod indicating portion  918  can be made more visible to the operator by, for example, painting it a bright color that contrasts with the color of the positioning system  50 . Any other suitable surface contrast can be utilized. 
         [0055]    Once the operator has sawed through the limb, the chain saw assembly  66  drops to the minimum angle  908 ′. Potential wear and damage to the arm  54 , pivot bracket  94  and mast  52  can be caused by this sudden drop. However, the drop is cushioned by the coil spring  920  compressing between the piston  922  and the rebound stop  924 . This cushioning effect is also advantageous when driving the vehicle over rough spots with the upper arm  54  extended. Additional cushioning can be provided by, for example, use of O-rings on either side of the coil spring  920 . 
         [0056]    While a coil spring shock absorber is described herein, it is understood that other types of shock absorbers  900  can also be used. For example, hydraulic and air shock absorbers can be utilized. 
         [0057]    When not in use, the indicating shock absorber can be disconnected from the pivot bracket  94  by removing a first pivot bolt  926  from an upper mount  928  of the shock absorber  900  and the pivot bracket  94 , or by removing a second pivot bolt  930  from the lower mount  932  of the shock absorber  900  and a mast bracket  934 , or both. 
         [0058]    Other indicating shock absorber configurations can also be used. For example,  FIG. 3G  and  FIG. 3H  illustrate an indicating shock absorber  900  attached to the upper arm  54  and the mast  52  within the inside angle between the upper arm  54  and the mast  52 . 
         [0059]    Referring now to  FIG. 5 , another positioning system  250  includes a telescoping mast hydraulic cylinder  252  attached at one end to a bracket  254  attached to the outer mounting member  68  of the telescoping mast  52  and at the other end to a bracket  256  attached to the slidably extending inner member  70  of the telescoping mast  52 . Hydraulic lines  258 ,  260  connect the telescoping mast hydraulic cylinder  252  to a hydraulic power source (not shown) on the tractor T. The positioning system  250  shown in  FIG. 5  permits hydraulic control of both the telescoping mast  52  by the telescoping mast hydraulic cylinder  252  and the saw blade assembly  66  by the hydraulic cylinder  100 . It will be understood by one skilled in the art that the positioning system  252  shown in  FIG. 5  is a modification of the positioning system  50  shown in  FIGS. 1, 2, and 4 , wherein the modification consists of the use of the telescoping mast hydraulic cylinder  252  to control the length of the telescoping mast  52  and eliminates the need for the locking pin  92 . 
         [0060]    Referring now to  FIG. 6 , the upper arm  54  of the positioning system  50  houses a chain oil reservoir  270 . A threaded vented cap  272  extends through a bore  274  in the upper arm  54  to engage a threaded bore  276  in the chain oil reservoir  270 . A chain oil reservoir fitting  278  in the oil reservoir  270  permits chain oil to flow from the chain oil reservoir  270  through the chain oil line  148  to a mounting plate fitting  280  and through a spacer  282  containing chain oil transfer channels  284 ,  286 ,  288 , and  290  (See  FIG. 11 ). 
         [0061]    Referring now to  FIG. 6  in conjunction with  FIGS. 1-5 , the chain oil from the chain oil reservoir  270  is gravity fed through the oil line  148  to the mounting plate fitting  280  when the chain saw assembly  66  extends downwardly from the pivot plate  94  after cutting the target limb L (See especially  FIG. 1 ). The bore  274  is sized so as to permit the threaded vented cap  272  to pass through the bore  274  with slight clearance. When the threaded vented cap  272  is threaded into the threaded bore  276  in the chain oil reservoir  270 , the threaded vented cap  272  secures the chain oil reservoir  270  within the upper arm  54 . Although square tubing is especially well suited for disposing a relatively smaller size within a relatively larger size to achieve a snug fit of the smaller square tubing within the larger square tubing, the upper arm  54  and the chain oil reservoir  270  can be of any suitable configuration. 
         [0062]    Referring now to  FIG. 7 , detachment of the hydraulic cylinder  100  of the positioning systems  50  and  250 , or disconnection of one end of the limit strap  152  of the positioning system  150 , permits the upper arm  54  to pivot on the pivot bolt  96  so the upper arm  54 , the mounting plate  64 , and the saw assembly  66  (or other tool attached to the mounting plate  64 ) can swing along an arc  294  between an extended use position, shown in phantom, and a folded storage position. 
         [0063]    Referring now to  FIG. 8 , another positioning system  350  has a telescoping upper arm  354  consisting of a telescoping upper arm outer member  356  and a slidably extending inner member  358  for locating the mounting plate  64  (and the saw assembly  66  attached thereto) at a convenient position distal from the pivot bracket  94 . A telescoping upper arm hydraulic cylinder  360  is attached at one end to a bracket  362  on the outer member  356  of the telescoping upper arm  354  and at the other end to a bracket  364  on the slidably extending inner member  358  of the telescoping upper arm  354 . Hydraulic lines  366 ,  368  connect the telescoping upper arm  354  hydraulic cylinder  360  to a hydraulic power source (not shown) on the tractor T. 
         [0064]    Referring now to  FIG. 9 , another positioning system  450  is similar to the positioning system  50  shown in  FIG. 7  except for the longitudinal alignment of the pivot bracket  94 , upper arm  54 , the mounting plate  64 , and the saw blade  118  along a common center line  452 . The alignment along the common center line  452  permits a more compact arrangement when the saw assembly  66 , the mounting plate  64 , and the upper arm  54  are folded along  294  for storage. 
         [0065]    Referring now to  FIGS. 10 and 11 , the mounting plate  64  is attached near the distal end  62  of the upper arm  54  by bolts  552 ,  554  disposed through bores  556 ,  558 , respectively in the mounting plate  64 , through bores  560 ,  562 , respectively near the distal end of the upper arm  54 , and secured by nuts  564 ,  566 , respectively. The mounting plate  64  attached to the distal end  62  of the upper arm  54  supports the chain saw assembly  66 . The chain saw sprocket drive  112  driven by the shaft  114  from the hydraulic motor  116  is aligned with the chain saw blade  118  having elongated slots  120 ,  122  for tension adjustment. The chain  124  engages the chain saw sprocket drive  112 . The position of the chain saw blade  118  with respect to the sprocket drive  112  determines the tension on the chain  124 . Bolts  126 ,  128  extending through bores  130 ,  132  in the chain saw blade locking plate  134 , through the elongated slots  120 ,  122  in the chain saw blade  118 , and through bores  136 ,  138  in the mounting plate  64  are secured by nuts  140 ,  142 . Hydraulic lines  144 ,  146  connect the hydraulic motor  116  to a hydraulic power source (not shown) on the tractor T. An oil line  148  provides gravity feed of oil from an oil reservoir (See  FIG. 6 ) to the chain  124 . 
         [0066]    Still referring to  FIGS. 10 and 11 , the spacer  282  is held between the saw blade  118  and the mounting plate  64  by bolts  126 ,  128  secured in place by nuts  140  and  142 , respectively. An adapter  576  is keyed inwardly to the shaft  114  and outwardly to the drive sprocket  112 . The drive sprocket  112  and the adapter  576  are secured to the keyed end  578  of the shaft  114  by a set screw (not shown). It will be understood by one skilled in the art that the drive sprocket  112  and the adapter  576  may, optionally, be integrated in a single drive sprocket keyed inwardly to the shaft  114 . 
         [0067]    Referring now to  FIG. 11 , the spacer  282  includes oiling channels  284 ,  286  on one side and oiling channels  288 ,  290  (not shown) on the other side. The oiling channels permit chain oil to move from the mounting plate fitting  280  (See  FIG. 4 ) to mating oiling channels in the saw blade  118 . It will be understood by one skilled in the art that oiling channels are standard construction for chain saw blades and are well known in the art. Bores  582 ,  584  in the spacer  282  connect oiling channels on opposite sides of the spacer  282 . Bores  586 ,  588  receive bolts  126 ,  128 , respectively for attachment of the saw blade  118  to the mounting plate  64 . It will be further understood by one skilled in the art that the thickness of the spacer  282  is a design choice dictated solely by the need to align the saw blade  118  with the drive sprocket  112 . 
         [0068]    Referring now to  FIGS. 12-15 , another positioning system  550  according to applicant&#39;s invention includes a chain oil reservoir  570  within the upper arm  54 . A threaded unvented cap  572  extends through a bore  574  in the upper arm  54  to engage a threaded bore  576  in the chain oil reservoir  570 . As illustrated in  FIG. 12 , a pump assembly  580  (See  FIG. 14 ) automatically pumps chain oil from the chain oil reservoir  570  to the chain  124  on the blade  118  each time the upper arm  54  and the chain saw assembly  66  mounted thereon are forced against a target limb L along arrow  118 . An actuating member  578  attached to the upper end portion  58  of the mast  52  contacts a spring-biased open piston  582  in hydraulic communication with a cylinder  583 . A suction check valve  584  connected the cylinder  583  to the chain oil reservoir  570  prevents chain oil from flowing from the cylinder  583  into the reservoir  570 , while a discharge check valve  586  permits oil to flow through the oil line  148  to the mounting plate fitting  280  on the mounting plate  64  and then through the spacer  282  to oil the chain  124 . 
         [0069]    Still referring to  FIGS. 12-15  and more particularly to  FIG. 13 , when the force on the actuating member  578  is relieved, a spring  588  effects a suction stroke. Chain oil is prevented from flowing backward through the discharge check valve  586  into the cylinder  583 , so chain oil is drawn into the cylinder  583  through the suction check valve  584 . When the upper arm  54  is once again moved downwardly along arrow  118  against a target limb L, the pump assembly  580  once again delivers oil to the chain. 
         [0070]    Although the chain saw assembly  66  described herein is powered by a hydraulic motor, it will be understood by one skilled in the art that the chain saw assembly could also be powered by a pneumatic motor (requiring only a singly air line for power) or an electric motor (requiring an electric power line and a generator). Similarly, pneumatic positioners could be used in place of the hydraulic cylinders  100 ,  252 . 
         [0071]    Referring now to  FIG. 16 , a top view of another positioning system  650  is shown with the mast  52 , the pivot bracket  94 , and the proximate end portion  60  of the upper arm  54  cut away. A vertical pivot bolt  652  disposed in vertical bores (not shown) near the distal end  62  of the upper arm  54  and through aligned vertical bores  654  (not shown) in mating horizontal tabs  656  secured to the mounting plate  64 . A hydraulic cylinder  658  is attached on one end to a bracket  660  on the upper arm  54  and on the other end to a bracket  662  on one of the horizontal tabs  656 . Hydraulic lines  664 ,  666  connect the hydraulic cylinder  658  to a hydraulic power source (not shown) on the tractor T. Operation of the hydraulic cylinder  658  along  668  causes the mounting plate  64  and the chain saw assembly  66  (or other tool attached to the mounting plate  64 ) to swing laterally along arrow  670 . 
         [0072]    Referring now to  FIG. 17 , the positioning system  650  shown in  FIG. 16  provides positioning of a nozzle assembly  680  connected to a supply hose  682 . The supply hose  682  may provide air for thinning fruit, an appropriate chemical mixture for spraying trees and other plant life, or paint for use on difficult-to-reach locations. A collar  684  secures the nozzle assembly  680  to an adaptor  686 . 
         [0073]    Referring now to  FIGS. 18 and 19 , another positioning system  750  is shown mounted in inner bottom  752  of a dirt bucket B. A four-point linkage assembly  760  is formed by a horizontal base  762 , parallel vertical members  764 ,  766  of equal length, and a horizontal top  768 . The horizontal base  762  consists of two parallel L-shaped members  770 ,  772  secured to the inner bottom  752  of the dirt bucket B by bolts  774  and nuts  776 . One end of the vertical member  764  is pivotally attached to the horizontal base  762  by a left bottom pivot bolt  778 , and one end of the parallel vertical member  766  is pivotally attached to the horizontal base  762  by a right bottom pivot bolt  780 . The horizontal top  768  consists of two parallel L-shaped members  782 ,  784 . The other end of the vertical member  764  is pivotally attached to the horizontal top  768  by a left top pivot bolt  786 , and the other end of the vertical member  766  is attached to the horizontal top  768  by a right top pivot bolt  788 . A hydraulic cylinder  790  is attached at one end to a mounting tab  792  attached to the horizontal base  762 . The other end of the hydraulic cylinder  790  is attached to a mounting tab  794  located on the inside of the vertical member  766 . The mast  52  is attached to a middle portion  796  of the horizontal top  768 . Movement of the hydraulic cylinder  790  along  798  causes the mast  52  to move responsively along  800  while maintaining the mast  52  perpendicular to the horizontal top  768 . 
         [0074]    The present invention has been described as a positioning system because it is adaptable for use with a variety of ground-based vehicles to which the assembly  52  is attached. The mast  52 , and thus applicant&#39;s positioning system generally, can be attached, by way of illustration and not by way of limitation, to an upstanding sidewall of a pickup bed, to a bale spike frame, to a skid loader, to a backhoe, or to an ATV. While attachment to a pickup bed may not permit use of hydraulic cylinders, an air compressor mounted in the pickup bed can be used to operate pneumatic cylinders (also referred to herein as pneumatic positioners). 
         [0075]    It will also be understood by one skilled in the art that the present positioning system invention is well suited for placing a variety of tools in hard-to-reach locations such as trees. 
         [0076]    From the above description, it is clear that the inventive concept(s) disclosed herein is well adapted to carry out the objects and to attain the advantages mentioned herein as well as those inherent in the inventive concept disclosed herein. While exemplary embodiments of the inventive concept disclosed herein have been described for purposes of this disclosure, it will be understood that numerous changes may be made which will readily suggest themselves to those skilled in the art and which are accomplished without departing from the scope of the inventive concept disclosed herein.