Abstract:
A pruner assembly having hollow shaft with a longitudinal axis, a lower end, and open upper end, and a handgrip portion slidable along the longitudinal axis between a first and a second position. A shearing mechanism attaches to said open upper end of the hollow shaft, which mechanism includes a body having a hook adapted to receive and hold a limb, a cutting blade pivots on the body and against the hook to cut the limb. An arm member pivots to the body and couples to the blade so that pivotal movement of the arm member pivotally moves the cutting blade. A pulley is mounted to the arm member distal end and a cable guide pulley is coupled to the hollow shaft adjacent the open upper end for guiding a cable into and out of the open upper end without the cable contacting the walls thereof. A cable is provided for moving the cutting blade with respect to the hook. The cable extends in operable engagement with the arm pulley and the guide member pulley, thus forming a two-pulley system for reducing the pull force needed to operate the assembly and cut the limb. The above mentioned pruner design applies to both fixed and adjustable length pruners.

Description:
FIELD OF THE INVENTION 
     This is a continuation application of U.S. patent application Ser. No. 09/072,123 filed May 4, 1998, now U.S. Pat. No. 6,038,773 which is a continuation-in-part application of U.S. patent application Ser. No. 08/722,792, filed Sep. 27, 1996 now U.S. Pat. No. 5,745,998, issued May 5, 1998, which is a continuation application of U.S. patent application Ser. No. 08/585,120, filed Jan. 11, 1996 now abandoned. 
    
    
     This invention relates to cutting tools, and more particularly, to pruning shears having an extended handle for reaching branches at greater heights, and a cord for remotely activating a shearing mechanism. 
     BACKGROUND OF THE INVENTION 
     Conventional tree pruning shears are typically provided with a pole of fixed or adjustable length, a shearing mechanism located at one end of the pole, and an operating cable or cord attached to the shearing mechanism and extending the length of the pole for remote operation of the shearing mechanism. 
     The conventional shearing mechanism usually includes a capturing hook portion which is adapted to bang from a branch or limb intended to be cut, and a mating pivotal cutting blade. The cutting blade includes a leverage arm from which is attached one end of the operating cord. The pruning shears are manipulated by holding the pole in one hand and the operating cord in the other hand . A limb of interest is “hooked” and held by the hook portion of the shearing mechanism. The operating cord is then pulled which causes the cutting blade to pivot into the “captured” limb. The amount of force required to cut the limb varies, depending on the type of wood, the size of the limb and the location of the cut. However, for the most part, the cutting action requires a great deal of force from its operator. 
     In addition, generally the operating cord hangs freely outside the pole. During the cutting operation, the operating cord will frequently become snagged on other branches or twigs, reducing the cutting force, and requiring time and effort to untangle the operating cord. 
     Another technical problem to be solved is related to certain user needs for an extendable pruner, that is one which can be extended and locked into a number of effective operating pruner lengths for a pruner having design benefits as described above. 
     While these other units may be suitable for the particular purpose for which they were intended, or for general use, they would not be as suitable for the purposes nor include the benefits of the present invention as described herein. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an adjustable length pruner which will effectively cut a branch with minimal effort. 
     It is another object of the invention to provide an adjustable length pruner in which the possibility of snagging the operating cord is greatly reduced. 
     It is a further object of the invention that the cutting arm is operated by means of a leverage arm, and the leverage of the cutting arm is greatly increased by the dual-pivotal attachment of the leverage arm and cutting arm. 
     It is a further object of the present invention to provide a pruner in which the operating cord extends through the interior of the pruner and has a portion operably coupled to a lower longitudinally operating handle of the pruner. 
     A further object of the present invention is to provide a pruner having an internally extending operating cord as described, which pruner can be extended and secured in a plurality or infinite number of operating pruner lengths. 
     Yet a further object is to provide a pruner with a shearing mechanism that includes a leverage arm and blade design that produces enormous cutting forces given the longitudinal displacement of the cutting shaft or handle. 
     A portable pruner for cutting limbs comprises a hollow elongated tube assembly having a longitudinal axis, a lower sliding portion and an upper open end. The sliding portion is telescopically slidable along the longitudinal axis between a first and a second position. A shearing mechanism is attached to the upper open end of the hollow handle and includes a body having a hook adapted to receive and hold a limb. A cutting blade assembly including a leverage arm is pivotally attached to the body and selectively pivots against the hook to cut the selected limb. The pruner includes means for pivoting the cutting blade with respect to the hook wherein the pivoting means is responsive to movement of the sliding portion between the first and second positions. 
     The upper section of the pruner is tubular. An operating cord extends through the upper open end then through the interior of the tube and has one portion operable by the sliding portion. Another portion of the cord extends beyond the open upper end and operably engages the leverage arm assembly so that longitudinal withdrawal of the sliding portion causes cutting rotation of the leverage arm and cutting blade assembly. 
     In one exemplary embodiment the upper section or hollow tube has a fixed length. 
     In another exemplary embodiment, the upper section or hollow tube includes two telescoping segments and an operable clamping or securing device mounted to the outer segment to enable the user to adjust the overall operating pruner length to any desired length within two limits. The device is selectively moveable on one of the two segments and the cord operatively engages the device so that length adjustment of the two segments also accommodates the change in cord length external to the hollow tube. This permits the same, relative operating positions of the handle and hollow tube regardless of the adjusted length of the hollow tube. 
     Other principal features and advantages of the invention will become apparent to those skilled in the art upon review of the following drawings, the detailed description and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, like elements are depicted by like reference numerals. The drawings are briefly described as follows. 
     FIG. 1 is a partial front plan view of the pruning shears, showing details of the shearing mechanism located in a receiving position, in accordance with the invention; 
     FIG. 2 is a side view of the shearing mechanism of FIG. 1, taken along the lines  2 — 2  of FIG. 1, in accordance with the invention; 
     FIG. 3 is a section view of a handle portion, in accordance with the invention; 
     FIG. 4 is a partial plan view of the pruning shears, similar to the view of FIG. 1, showing the shearing mechanism in a fully cut position; 
     FIG. 5 is a partial rear plan view of the shearing mechanism showing the shearing mechanism in the receiving position, in accordance with the invention; 
     FIG. 6 is a partial plan view of the shearing mechanism and the handle portion, in accordance with the invention; 
     FIGS. 7A and 7B are the same as FIG. 1 showing an exemplary embodiment that is length adjustable and wherein the length is adjusted to the approximate shortest position; 
     FIGS. 8A,  8 B and  8 C show the embodiment of FIGS. 7A and 7B adjustable to the approximate longest position and the handle withdrawn to the cut position; 
     FIG. 9 is a horizontal section taken along line  9 — 9  of FIG. 8B; 
     FIG. 10 is a partial view similar to FIGS. 7A and 7B showing an alternate embodiment with parts broken away. 
     FIG. 11 is a partial view of another embodiment showing a clamp that releasably secures the pole segments and releasably secures the outer cable portion. 
     FIG. 12 is similar to FIG. 11 of yet another embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 6, a pruning apparatus  10  in accordance with the invention is shown having a handle assembly  12 , and a shearing mechanism  14 . The shearing mechanism  14  includes a body  16  defining a tube  18  (which is open at both ends), a hook plate  20  having a hook  22 , a cutting arm  24 , and a leverage arm  26 . 
     As shown in FIGS. 2 and 3, the handle assembly  12  includes a hollow shaft  27 , defining a longitudinal axis and having an open upper end  28 , a lower end  30 , and a slidable grip portion  32 . An upper foam rubber or plastic hand grip  30  surrounds the lower end of shaft  27 . The slidable grip portion  32 , further comprises an end foam or plastic hand grip  32 E, fully opposite from the shearing mechanism  14 , and may comprise a weighted sleeve  32 W. The weighted sleeve  32 W may be constructed of metal, wherein the majority of the other non-moving, non-cutting parts may be constructed of plastic. The metal components of the shearing mechanism  14  tend to make the pruning apparatus  10  top heavy. Thus, the weighted sleeve  32 W helps balance the pruning apparatus  10  by counteracting the weight and rotational moments of shearing mechanism  14 . Ideally, the weighted sleeve  32 W is weighted so that the shearing mechanism  14  is responsive to the slightest effort by the user at the slidable grip portion  32 . Thus, any effort or force expended by the user is translated into cutting power, and increased torque at the cutting blade helps increase the cutting arm  24 . In addition, the end grip  32 E may itself have an end grip weight  32 B. 
     The shearing mechanism  14  is attached to the open upper end  28  of the hollow shaft  27 . The open upper end  28  of the hollow shaft  27  is positioned within the tube  18  of the shearing mechanism  14  and held in place using appropriate fasteners or a conventionally known clamping action generated by controlled deformation of the tube  18 . The hook plate  20  is firmly attached to the body  16  using an appropriate fastener  34 , such as rivets or bolts. The cutting arm  24  is pivotally connected, using an appropriate bolt  36 , to an upper portion of the hook plate  20  at a cutter pivot point  38  which is located adjacent to the hook  22 , as seen in FIG.  1 . The cutting arm  24  is pivotal between an open pre-cut position, as shown in FIG. 1, and a closed fully-cut position, as shown in FIG.  4 . The cutting arm  24  is preferably held in the open position by a spring bias. 
     Also seen in FIGS. 1 and 4 is the cutting arm  24 , which is attached to the hook plate  20  approximately at the middle of the cutting arm  24 . The cutting arm  24  includes an outwardly curved cutting edge  40  which begins adjacent the middle of the blade and extends along one edge to a cutter end  42  of the cutting arm  24 . Located opposite the cutter end  42  of the cutting arm  24  is a leverage end  44 . The cutting arm  24  upper portion is preferably angled inwardly, e.g. above hook  22 , from the cutter pivot point  38  at a prescribed angle. 
     The hook  22  is preferably curved downwardly, as shown in FIG. 1, and includes an inwardly curved cutting edge  46 . The downwardly curved hook  22  and accessible side  48  of the body  16  defines a receiving nook  50  which is adapted to receive a limb of interest. The exact size of the receiving nook  50  is dependent on the specific application of the pruning shears, i.e., the range of limbs intended to be pruned. Regardless, the shape of the cutting edge  46  mates (with a prescribed shearing overlap) with the outwardly curved cutting edge  40  of the cutting arm  24 . 
     Located along the accessible side  48  of the hook plate  20 , and within the receiving nook  50 , is an outwardly curved protrusion  52  which is adapted to outwardly force a captured limb into the cutting edge  46  of the hook  22  to assist in holding the limb in place prior to and during the shearing procedure. The protrusion  52  is aligned with and is shaped similar to the cutting edge  40  of the cutting arm  24  and further functions to effectively shield the cutting edge  40  when the cutting arm is located in the open position. 
     The leverage arm  26  is pivotally connected to the hook plate  20  at a leverage pivot point  54  which is adjacent to, but preferably not coaxial with the cutter pivot point  38 . In accordance with the invention, the leverage pivot point  54  is located a prescribed distance from the cutter pivot point  38  and a greater distance from the receiving nook  50 . A spring  55  is located at the leverage pivot point  54  and is adapted to bias the cutting arm  24  in its open position against a stop peg  57 , as illustrated in FIG.  2 . 
     The leverage end  44  of the cutting arm  24  is pivotally connected to the leverage arm  26 , at a connecting point  56 . The pivotal connection of the cutting arm  24  and the leverage arm  26  includes a slot  58  located within the leverage arm  26 . The slot  58  is necessary to compensate for the unequal arcs of movement between the cutting arm  24  and the leverage arm  26 , due to the displaced pivot points of the two arms. The leverage arm  26  is preferably outwardly angled, away from the cutting arm  24 , at a prescribed angle. 
     A leverage pulley  60  is attached to a remote end  62  of the leverage arm  26  and aligns approximately with the longitudinal axis of the hollow shaft  27 . A friction reducing guide pulley  64  is operatively attached to the body  16 , adjacent to the open upper end of the tube  18 . An anchor arm  66  is attached to the body  16  opposite the hook plate  20 , as shown in FIG.  1 . 
     A cable  68  positioned within the hollow shaft  27  is attached to the slidable grip portion  32  shown in FIG.  3  and extends upwardly through the tube  18  of the body  16 , around the leverage pulley  60  and is anchored to the anchor arm  66 . 
     In operation, referring to FIG. 4, the user captures a limb within the receiving nook  50 . The user pulls down on the hollow shaft  27  and forces the limb against the cutting edge  46 . Once the limb is positioned within the receiving nook  50 , the user moves the slidable grip portion  32  with respect to the hollow shaft  27 . The downward movement of the slidable grip portion  32  draws the cable  68  into the hollow shaft  27 , as seen in FIGS. 3 and 6 and indicated by the arrows  70  in FIG.  4 . The pulling of the cable  68  causes the leverage arm  26  to pivot about the leverage pivot point  54 , as indicated by the arrow  72 . The leverage pulley  60  introduces a leverage advantage to the pivoting of the leverage arm  26 , as is well known in the art so that the force applied to the slidable grip portion  32  is effectively doubled in pulling down the leverage arm  26 . It is important to note that one-handed operation is uniquely possible with the present invention. 
     As the leverage arm  26  pivots, the cutting arm  24  is forced to pivot about the cutter pivot point  38 , as indicated by the arrow  74  in FIG. 4, against the spring bias from the spring  55 . As soon as the leverage arm  26  and the leverage pulley  60  moves from alignment with the longitudinal axis, the cable  68  is “caught” and guided by the guide pulley  64 . The resulting movement of the cutting arm  24  with respect to the hook  20  cuts the captured limb. The reversed angles (outward/inward) of the leverage arm and cutter blade bends and cooperates to increase the cutting force of blade  40 . 
     Once the limb is cut, the user releases the slidable grip portion  32 . The spring  55  shown in FIG. 2 causes the cutting arm  24  to return to the open position, as indicated by the arrow  80 , of FIG. 5, and the leverage arm  26  to move upwardly to its pre-cut position, as indicated by the arrow  82  in FIG.  5 . The cable  68  similarly returns to its pre-cut position, as shown by the arrows  84 . 
     With reference to FIGS. 7-9, there is shown an exemplary length-adjustable pruner according to the principles of thc present invention. Pruner  100  includes shearing mechanism  101 , the structure, function, and operation of which can be the same as described above with the addition of cable guide, pulley or roller  103 . If desired, a cable guide with a rounded surface can be used instead of a pulley or roller. The handle assembly  102  includes hollow outer segment or pole  106  and a hollow inner segment or pole  104  that telescopes through the upper end of pole  106 . Shearing mechanism  101  is mounted in fixed relation to the upper end of pole  104 . Handle  102  further includes a sliding shaft  112  telescoping through the lower end of pole  106 . Foam rubber or other suitable material hand grips  108  and  114  are secured at the lower end of pole  106  and lower end of shaft  112 , respectively, to aid the user gripping integrity and manual frictional engagement with the pruner. Grip  108  includes a protecting piece  110  that overlaps the lower edge of pole  106 . Hand grip  114  includes shield  115  that extends beyond the bottom of pole  106  to protect the user&#39;s upper or lower hand from being pinched when shaft  112  is moved to the pre-cutting or ready position shown in FIG.  7 . Shield  115  can be made of any suitable material such as plastic, rubber, or metal. Alternatively, the shield can be mounted on the lower end of grip  112  and facing downward, if desired. 
     The cable includes inside cable portion  116  with, in this example, its distil end  117  connected to the upper part  117  of shaft  112  and outer cable potion  118 . Handle  102  further includes a pole extension clamp  109  permanently mounted to or near the top of pole  106 . The upper part of clamp  107  is dimensioned to closely but slidably fit around pole  104 . Wing screw  128  enables the user to tighten or loosen the clamp for frictional engagement with or release between pole  104  and clamp  107 . Upon such release, poles  104  and  106  can telescope to new overall length positions. Then wing screw  128  can be tightened to clamp poles  104  and  106  at such new length. As better seen in FIG. 9, clamp  107  can include a u-shaped outside cable guide  113 , if desired. 
     In order to accommodate the overall length adjustment, handle  102  further includes a cable clamp  124  dimensioned slightly larger than the outside diameter of pole  106 . Clamp  124  includes a wing screw or nut  126  to secure clamp  124  firmly at a suitable position to avoid unwanted slack or tension in inside cable portion  116  and/or outside cable portion  118  when shearing mechanism is in the pre-cutting condition, such as shown in FIG.  7 . In this exemplary embodiment shown, the end of cable portion  118  extends through a portion of clamp  124  and washer  122 . The distil end of portion  118  terminates in a threaded screw held to the cable by coupler  125  and tension wing nut  120  can be turned to fine tune the slack or tension on the cable as desired. 
     In operation, the operator loosens knob  128  and knob  126 . Poles  106  and  104  are telescoped relative to each other to a desired overall length. The wing knobs  126  and  128  are then firmly tightened to fix the overall pruner length and the cable length. If necessary, wing nut  120  can be turned to finely adjust the tension in the cable. The pruner is then ready for use in cutting a limb as described above. After use, knobs  128  and  126  can be loosened to telescope poles  104  and  106  to the shortest overall length for storage or for use in place of a lopper. 
     An alternate exemplary embodiment is shown in FIG. 10 in which the inner and outer telescoping pole segments  104  and  106  are reversed so that segment  106  slides within segment  104 . In this embodiment extension pole clamp  107  is reversed and fixed to the bottom of segment  106  and releasably clamped to pole segment  104 . Cable clamp  124  is slidably mounted on upper pole segment  104  between a first position just above extension clamp  107  and a second position just below shearing mechanism  101 , as shown. This arrangement of parts yields the benefit of shortening the length of cable needed for overall extension and operation compared to the embodiment as shown in FIGS. 7-9. 
     Yet a further exemplary embodiment is shown in FIG. 11 wherein the pole extension clamp  107 A is permanently connected to the top of lower pole  106  and releasably connected to upper pole segment  104  as described for the embodiment of clamp  107  of FIGS. 7-9. Clamp  107 A also includes a cable anchor or strap  140  having one end connected, for example riveted, to the wing  141  of clamp  107 A and the other end releasably connected to the wing  143  clamp  107 A by wing nut or screw  142 . The outer cable portion  118  runs downward between strap  140  and the body of clamp  107 A and, if desired, upward around strap  140  thence downward again between strap  140  and the body of clamp  107 A generally as shown. Clamp  107 A and strap  140  function to not only releasably clamp the telescoping segments  104  and  106  at desired lengths but also function to releasably clamp the outer cable portion  118  at various corresponding lengths to accommodate the relative positions of pole segments  104  and  106 . Accordingly, the embodiment of FIG. 11 needs no separate cable clamp such as  124  in FIG. 10 and 124 in FIG.  7 . 
     In operation, wing-nut  142  is loosened to release the clamp force between strap  140  on cable portion  118 . If the pruner length is to be increased, the operator draws portion  118  upward to provide more length or slack. Wing-nut  128  is loosened and the pole segments telescopically withdrawn until the desired length is reached. Wing-nut  128  is then tightened to fix the length and portion  118  is fed or drawn downward about strap  140  until the operative length of portion  118  accommodates the newly set pruner length. With portion  118  so set, wing-nut  142  is tightened to clamp or firmly fix the cable against the body of clamp  107 A. 
     The alternate embodiment shown in FIG. 12 includes segment extension and cable clamp  107 B permanently connected to the top of segment  106  and releasably clamping or securing segment  104  by operation of wing-nut or wing-screw  150 . Cable portion  118  extends downward between flanges  152  and out the vertical edges thereof below wing-nut  150 . Accordingly, selective operation of wing-nut  150  not only releasably secures segment  104  to clamp  107 B but it also releasably clamps or secures portion  118  between flanges or wings  152 . Loosening of wing nut  150  enables selecting the length of the pruner and the corresponding proper operable length of cable portion  118  above flanges  152 . 
     It should be understood that the various parts can be made of any suitable materials and the parts are not necessarily drawn to scale. For example, poles  104  and/or  106  can be made of plastic, fiberglass, or metal. The cable can be made of metal, chain, nylon tape, nylon cord, or any other suitable materials and types. It should also be understood that the cable route shown is exemplary but is preferred since it yields benefits such as simplicity in design, increased reliability, ease of use in tight limb environments, and two-hands on the handle  114 , if desired. 
     Other and further changes and modifications can be made to the herein disclosed embodiments without departing from the spirit and scope of the present invention.