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Publication numberUS3835535 A
Publication typeGrant
Publication dateSep 17, 1974
Filing dateAug 20, 1973
Priority dateAug 20, 1973
Publication numberUS 3835535 A, US 3835535A, US-A-3835535, US3835535 A, US3835535A
InventorsJ Robison, H Eads
Original AssigneeMc Donough Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Pole pruner with improved cutting head
US 3835535 A
Abstract
A pole pruner having a cutting head of the single anvil type in which the cutting blade is formed of a relatively thin blade structure having an essentially single bevel construction with a non-symmetrical straight cutting edge, the cutting blade being arranged with respect to the fixed anvil member shape and location so that the free end of the cutting blade is slidably supported by the fixed anvil member during the portion of the cutting stroke where binding and lateral flexure is most likely to occur.
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United States Patent Robison et al.

[ 1 Sept. 17,1974

POLE PRUNER WITH IMPROVED CUTTING HEAD Inventors: James W. Robison, Belpre, Ohio; Harold O. Eads, Parkersburg, W. Va.

Assignee: McDonough C0., Parkersburg, W.

Filed: Aug. 20, 1973 Appl. No.: 389,548

US. Cl. 30/249, 30/166 Int. Cl B26b 13/06, B26b 13/22 Field of Search 30/166, 231, 244, 245,

References Cited UNITED STATES PATENTS 5/1912 Higley 5/1923 Barrett 2/1970 Ballard 30/244 X 3,715,805 2/1973 Fraser 30/166 FOREIGN PATENTS OR APPLICATIONS 1,065,804 4/1967 Great Britain 30/246 Primary ExaminerAl Lawrence Smith Assistant Examiner.l. C. Peters Attorney, Agent, or FirmCushman, Darby & Cushman [5 7 ABSTRACT A pole pruner having a cutting head of the single anvil type in which the cutting blade is formed of a relatively thin blade structure having an essentially single bevel construction with a non-symmetrical straight cutting edge, the cutting blade being arranged with respect to the fixed anvil member shape and location so that the free end of the cutting blade is slidably supported by the fixed anvil member during the portion of the cutting stroke where binding and lateral flexure is most likely to occur.

15 Claims, 9 Drawing Figures PAIENIEBsEr .1 mu

Sam 2m 3 POLE PRUNER WITH IMPROVED CUTTING HEAD This invention relates to pole pruners and more particularly to improvements in pole pruners which render the same capable of cutting with greater efficiency and less bending action.

Pole pruners have been known for many years. In general, a pole pruner includes an elongated handle, a cutting head assembly on one end of the handle which includes a fixed member operable to be engaged with a limb or the like and a movable member operable to be moved through a cutting stroke with relation to the limb engaged by the fixed member. Pole pruners usually include a rope and pulley assembly which is operatively connected with the movable member and extends to the opposite end portion of the handle for effecting movement of the movable member through its cutting stroke in response to a manually efiected pull and a spring assembly, usually connected between the fixed and movable members of the cutting head assembly, for effecting a movement of the movable member through a return stroke.

The biggest problem presented in the operation of pole pruners of the type noted above occurs when the operator attempts to use the pole pruner to cut a limb of a size which is close to the maximum size within the operative range of the tool. The problem presented is not so much a cutting problem as it is a binding problem in that the capability of effecting a cutting action is clearly present, but in the attempt to achieve the capability, the cutting action is prevented due to the binding of the cutting blade within the limb which is to be cut. This binding problem is particularly aggravating when it is considered that the cutting action takes place at the end of a handle with a length of as much as l2 feet which is often held by the operator over his head. Once the binding action occurs, it becomes extremely difficult for the operator to release the cutting blade since the only force tending to effect release is provided by the spring. Severe damage to the device can be inflicted when the operator attempts to extricate the tool from a situation of this type.

Many of the pole pruners currently available commercially utilize as a part of the movable member a relatively thin cutting blade having a symmetrical double beveled cutting edge disposed in the center of the blade thickness. The fixed member utilized with double beveled cutting blades is invariably of a split anvil construction providing two spaced rigid portions which engage the limb in opposed relation to the direction of cut on opposite sides of the plane of the cutting edge. When it is considered that the normal direction of the cutting blade is upwardly in relation to the limb so that the weight of the limb tends to provide a binding force as the cutting action proceeds, it can be further appreciated that the application of downward forces on opposite sides of the cutting plane by the split anvil tends to materially add to the binding action present in a manner which increases in response to increases in the actuating pull force. Over the years, there have been many proposed solutions to the binding problems presented by the conventional double beveled cutting edgesplit anvil cutting heads. For example, it has been proposed to mount the cutting blade so that it cuts downwardly so as to utilize the weight of the limb being cut to alleviate binding (see US. Pat. No. 988,153), but

2 this proposal has not been adopted commercially .as the solution.

Of course, the binding problem canbe eliminated by limiting the maximum capacity of the tool. But this solution merely results in the necessity of the operator to pay the additional costs of a more expensive too]. One such tool currently available commercially utilizes two cast iron members of relatively thick size which are precision ground to provide a curved cutting edge on the fixed limb engaging member and a curved single bevel cutting blade on the movable member. The relationship between these two cutting edges is such that when the operator attempts .to cut a limb which is of a size slightly greater than that which can be received within the fixed member, the curvature ,of the cutting blade tends to move the limb out of the path of movement of the blade away from engaged relation to the fixed member. When a cutting action is achieved within the maximum limb size, the arrangement, due to the elimination .of the aforesaid binding forces provided by a split anvil construction, does not tend to bind in the same manner as stated previously. The binding forces imposed on a single bevel-single anvil arrangement while eliminating the inherent binding action of the double bevel-split anvil arrangement, nevertheless presents an inherently different problem which is related to binding. Thus, when a single bevel nonsymmetrical cutting blade is moved through a maximum size limb, there is imposed upon the blade binding forces having a lateral resultant component which tends to bend the blade. Once the blade is bent beyond its elastic limit, the situation can only get worse because the unbalanced lateral component increases with increased flexure. To preclude this action, the blade member of the prior art cutting head is made of cast iron of a thickness to resist flexure beyond the elastic limit of the material. A point of diminishing return is rapidly encountered however, since increasing the blade thickness increases the binding forces imposed thereon. Moreover, as previously indicated, a construction of this type is quite costly because of the precision grinding which must be performed.

An object of the present invention is to provide a pole pruner which achieves the advantages of known single bevel-single anvil arrangements in terms vof the elimination of the binding tendencies inherent in the known double bevel-split anvil arrangements, while still obtaining the economical advantages of the latter which heretofore have not been achieved in the known single bevel-single anvil arrangements. In accordance with the principles of the present invention, this objective is obtained by utilizing arelatively thin blade member of a construction similar to that heretofore utilized in the symmetrical double bevel arrangements but having an essentially single bevel arrangement with a nonsymmetrical straight cutting edge. By then relating the shape and location of the cutting blade with the shape and location of the free end portion of the fixed member so that the free end of the cutting blade is slidably supported by the fixed member during the portion of the cutting stroke where binding or lateral flexure is most likely to occur, both binding and flexure are substantially eliminated. The added resistance to the cutting movement occasioned by the aforesaid sliding action can be reduced to a negligible factor by suitable antifriction material such as conventional lubrication or, more conveniently, by providing the cutting blade with a Teflon coating. To insure proper operation, the fixed member is provided with a cam surface at the position of initial overlap during the cutting stroke which merges into the planar sliding surface thereof.

Another object of the present invention is the provision of an improved combined rope guide and handle part clamping assembly in a pole pruner of the type embodying a telescopic handle assembly which provides for increased effectiveness both in the telescopic adjustment of the handle assembly and in the operation of the rope and pulley assembly for actuating the cutting head.

Still another object of the present invention is the provision of a pole pruner of the type described which is simple in construction, efficient and durable in operation, and economical to manufacture.

These and other objects of the present invention will become more apparent during the course of the following detailed description and appended claims.

The invention may best be understood with reference to the accompanying drawings wherein illustrative embodiments are shown.

IN THE DRAWINGS:

FIG. 1 is a side elevational view of a pole pruner embodying the principles of the present invention;

FIG. 2 is an enlarged fragmentary elevational view of the cutting head assembly of the pole pruner shown in FIG. 1, the movable member being shown in full lines in an intermediate position of movement through its cutting stroke and in phantom lines in a position at the completion of its cutting stroke;

FIG. 3 is a front elevational view of the stroke shown in FIG. 2;

FIG. 4 is a fragmentary sectional view taken along the line 44 of FIG. 2;

FIG. 5 is an enlarged fragmentary sectional view taken along the line 5-5 of FIG. 1;

. FIG. 6 is an enlarged'sectional view taken along the line 6-6 of FIG. 1;

FIG. 7 is a view similar to FIG. 1 illustrating a modified form of the handle construction of the pole pruner;

FIG. 8 is an enlarged fragmentary sectional view taken along the line 88 of FIG. 7; and

FIG. 9 is an enlarged sectional view taken along the line 99 of FIG. 7.

Referring now more particularly to FIG. 1 of the drawings, there is shown therein a pole pruner, generally indicated at 10, which embodies the principles of the present invention. The pole pruner 10 includes, in general, an elongated handle assembly, generally indicated at 12, which, as shown, is preferably of the telescopically adjustable type, a cutting head assembly, generally indicated at 14, on one end of the handle construction, a pruning saw 16 carried by the cutting head 14 and a rope and pulley assembly, generally indicated at 18, operatively connected with the cutting head and extending to the opposite end portion of the handle assembly for actuating the cutting head in response to a manually effected pull.

The cutting head assembly 14 consists essentially of a fixed member, generally indicated at 20, operable to be engaged with a tree limb or the like, a movable member, generally indicated at 22, operable to be moved through a cutting stroke with relation to the limb engaged by the fixed member 20 and the movable member 22 for effecting movement of the latter through a return stroke.

Referring now more particularly to FIGS. 2 and 3, the fixed member 20 is preferably in the form of a rigid metallic member, the specifically preferred form shown being punched from steel plate stock. As shown, the shape of the member is such as to include an end portion 26 adapted to be fixedly connected with one end of the handle construction, a fixed intermediate portion 28 extending generally longitudinally outwardly of the aforesaid end of the handle, a second intermediate portion 30 extending transversely from the first intermediate portion 28 and a free end portion 32 extending transversely inwardly from the second intermediate portion in spaced relation from the first intermediate portion 28.

The first intermediate portion 28 includes a straight limb engaging surface 34 which faces in a direction toward the free end portion 32 and the latter includes a limb engaging surface 36 which faces toward the first intermediate portion 28. Formed in the second intermediate portion 30 is a limb engaging surface 38 which extends between and interconnects the limb engaging surfaces 34 and 36. In the preferred embodiment shown, the limb engaging surface 38 is of arcuate configuration about a single axis which is tangential at one end to the straight surface 34. The limb engaging surface 36 of the free end portion 32, as shown, is generally straight and likewise is tangential to the opposite end of the surface 38. The straight surface 36 diverges in a direction toward the outer extremity of the free end portion 34 with relation to the straight surface 34 at an angle which is approximately 16.

It will also be noted that with the preferred embodiment shown wherein the fixed member 20 is formed of flat plate stock, the fixed member provides a common planar surface to all of the aforesaid portions thereof which intersects with the limb engaging surfaces 34, 36 and 38. It will also be noted that the fixed member 20, as shown, is preferably provided with a branch hook portion 40 extending from the first intermediate portion 28 in opposed relation to the limb engaging surface 34 thereof. It will be understood that the provision of the branch hook, while preferable, is an optional feature. Similarly, the provision of a pruning saw 16, while preferred, is likewise an optional feature. In this regard, it will be noted that the pruning saw provided is of a concavely curved type provided with cutting teeth of approximately five per inch. The pruning saw can be detachably fixedly secured to the fixed member 20 by any suitable means and, as shown, such means takes the form of an attaching pin 42 fixedly engaged to the second intermediate portion 30 and extending therefrom perpendicular to the aforesaid planar surface thereof for engagement within the base of the saw blade. The base of the saw blade includes a parallel opening which is adapted to register with an opening in the second intermediate portion 30 of the fixed member 20 for the purpose of receiving therethrough conventional fastening means 44, such as a bolt and wing nut assembly or thelike. As shown in FIG. 1, the base of the saw blade may be provided with a second fastener receiving opening for the purpose of providing angular adjustability of the position of the saw blade.

The movable member 22 is also preferably in the form of a rigid metallic member, the specific embodiment shown again being punched from plate steel stock and suitably heat treated. As shown, the movable member includes a cutting blade portion 46 and a lever arm portion 48. In accordance with the preferred construction as stated above, the movable member thus provides a planar surface which, when the movable member is mounted in operative relation with the fixed member, is disposed in coincidental relation with the aforesaid common planar surface of the fixed member 20. As shown, the movable member is mounted on the fixed member, as by a pivot bolt assembly 50, for pivotal movement between two limiting positions about an axis extending perpendicular to the aforesaid coincident planar surfaces which is disposed adjacent the juncture between the first and second intermediate portions of the fixed member and the juncture between the cutting blade and lever arm portions of the movable member 22.

The blade portion 46 has formed thereon a straight cutting edge 52, which substantially intersects the aforesaid planar surface thereof. As best shown in FIG. 4, the cutting edge is defined by a straight bevel configuration which includes first relatively narrow straight double bevel surfaces 54 which intersect with the cutting edge 52 and extend therefrom at an angle of approximately 45 with respect to a'flat plane intersecting the cutting edge parallel to the planar surface of the blade portion 46 and a second relatively wide straight bevel surface 56 which intersects with one side of the double bevel surface 54 and extends to the opposite surface of the blade portion at an angle of approximately 6-% with respect to the planar surface intersecting the cutting edge 52.

The straight bevel surface construction described above is from a functional standpoint a single bevel arrangement, despite the provision of the double bevel surfaces 54, since the construction is such that when the blade is moved through a limb or the like, the resultant lateral forces are imbalanced rather than balanced as in a double bevel arrangement. The construction can be considered a single bevel arrangement from a structural standpoint in that the cutting edge is not symmetrical with respect to the blade thickness. While the present invention clearly contemplates a construction in which the cutting edge 52 is defined by only a single first bevel surface 54 which extends all the way to the planar surface of the blade portion 46, the double bevel surfaces 54, as shown and described, are preferred because the resultant cutting edge is stronger and less subject to damage by engagement with the fixed member 20 due to lateral bending during operation because of the slight lateral offset between the cutting edge and the planar surface of the blade portion 46. Moreover, the present arrangement reduces the resultant lateral forces somewhat.

The movable member 22 is limited in its pivotal movement about the axis provided by the bolt assembly 50 between the aforesaid two limiting positions by any suitable means, such as a stop pin 58 extending from the lever arm portion 48 beyond the aforesaid planar surface thereof in a position to engage the rear surface of the second intermediate portion when in the limiting position into which it is urged by the spring 24 and to engage the rear surface of the first intermediate portion adjacent the hook portion when in the other limiting position.

During the movement of the movable member 22 from its spring urged limiting position to its other limiting position, the cutting blade portion 46 is moved through a cutting stroke. The location of the pivot pin 50 in relation to the fixed member 20 and movable member 22 is chosen so that at the beginning of the cutting stroke, the straight cutting edge 52 is disposed in substantial alignment with the straight limb engaging surface 34 of the first intermediate portion 34, as shown in FIG. 1, and, at the end of the cutting stroke the cutting edge 52 is disposed substantially at right angles to the surface 34 and in general alignment with the outermost portion of the limb engaging surface 38 of the second intermediate portion 30, as shown in broken lines in FIG. 2.

The location of the pivot pin 50 is so related to the longitudinal extent of the cutting blade portion 46 from the pivotal axis and the longitudinal extent of the free end portion 32 from the second intermediate portion that the outer extremity of the cutting blade portion 46 overlaps the outer extremity of the free end portion 32 when the cutting edge 52 reaches an angular position of approximately 45 with respect to the surface 34 during the cutting stroke, as shown in full lines in FIG. 2. As best shown in FIGS. 3 and 4, the outer extremity of the free end portion is provided with a cam surface 60 which merges with the planar surface thereof. As shown, the cam surface 60 is preferably provided by simply bending the outer extremity of the free end portion in a direction away from the cooperating planar surface of the cutting blade.

Referring now more particularly to FIGS. 1, 5 and 6, the handle assembly 12 includes a pair of handle parts 62 and 64 which, in the embodiment shown in FIG. 1, are arranged to be mounted in telescopic relation with respect to one another. The handle parts may be of any suitable construction and, as shown,.are of cylindrical tubular configuration made of aluminum. The cutting head 14 is secured to the end portion of the handle part 62 which extends outwardly from the handle part 64. While any suitable means may be utilized for effecting the connection between the handle part 62 and the fixed member 20 of the cutting head 14, as shown, the end portion of the handle part 62 is appropriately reenforced, as by a wooden core element 66, which is mounted within the end portion of the handle part 62 filling the interior thereof. A kerf 68 is formed in the outer end portion of the handle part 62 and core element 66 within which the end portion 26 of the fixed member 20 of the cutting head 14 is engaged. The end portion 26, handle part 62 and core element 66 are provided with registering openings extending therethrough in a direction transverse to the kerf 68 for receiving appropriate fastening elements, such as bolt assemblies 70 or the like.

The handle assembly 12 also includes means for fixedly securing the two handle parts 62 and 64 to gether in any desired position of telescopic adjustment which, as shown, is in the form of a combined clamp and rope guide assembly, generally indicated at 72, embodying the principles of the present invention. The preferred embodiment shown includes a pair of rigid metal plates each similarly shaped to provide a pair of longitudinally spaced generally semi-cylindrically configured portions 74 for embracing the handle parts adjacent their juncture, a fastener receiving tab 76 extending from one end of each semi-cylindrical portion 74, and an integral flat portion 78 extending from the opposite ends of the semi-cylindrical portions 74. The

flat portions 78 are interconnected in spaced relation by a series of fasteners 80, preferably in the form of shouldered rivets extending through one of the flat portions 78 and fixed to the other. As shown, two rivets are provided adjacent the semi-cylindrical portions 74 and a third rivet is disposed outwardly therefrom and has a pulley 82 journaled thereon between the associated plate portions78.

The two lower semi-cylindrical portions 74 are disposed in embracing relation to the end of the handle part 64 from which the handle part 62 extends and are detachably fixedly secured thereon by a suitable fastening element extending through the associated tabs 76 thereof. The two upper semi-cylindrical portions 74 are disposed in embracing relation to a split sleeve 84 slidably engaged on the exterior of the handle part 62. The split sleeve 82 is preferably made of nylon or the like and has one end thereof disposed in engagement with the adjacent end of the handle part 64. The sleeve is retained against longitudinal movement in a direction away from the handle part 64 by means of an exterior radial flange 86 extending between each pair of spaced cylindrical portions. In order to prevent rotation of the split sleeve 84, the latter may be provided with an enlarged portion adapted to be disposed between the plate portions 78. It will be understood that the upper two semi-cylindrical portions 74 are thus adapted to permit relative longitudinal telescopic movement of the handle part 62 with respect to the handle part 64. In order to fixedly secure the handle parts 62 and 64 in any position of telescopic adjustment, an appropriate fastener assembly 88 is provided between the associated tabs 76 for effecting the clamping action. As shown, the fastener assembly includes an eye-bolt having a nut threaded on the shank thereof. The shank extends through registering openings in the associated tabs, the opening opposite from the nut being of square configuration. A second nut is threadedly engaged on the outwardly extending end of the shank and has a keeper clip engaged thereon which has tabs thereon extending through the square opening to prevent rotation of the nut. With this type of assembly, the clamping action of the assembly 72 is achieved by turning the eyebolt of the assembly 88 in a direction to tighten the assembly.

As previously indicated, the pulley 82 of the assembly 72 provides a rope guiding function and thus forms part of the rope and pulley assembly 18. In the preferred embodiment shown, the rope and pulley assembly 18 embodies a single pulley arrangement although it will be understood that a plural pulley arrangement may be utilized if desired. The single pulley arrangement is preferred since it provides an optimum balance between mechanical advantage, efficiency and the linear extent of the pull required to accomplish movement of the blade portion through its cutting stroke.

The specific arrangement of the rope and pulley assembly 18 includes an elongated rope 90 having one end thereof knotted, as indicated at 92. From the knot 92, the rope extends through an opening 94 formed in the handle part 62 and core element 66 at a position spaced below the end portion 26 of the cutting head 14. From the opening 94, the rope 90 extends around a pulley assembly, generally indicated at 96, and then between the inner periphery of the guide roller 82 and the adjacent rivets 80. The opposite end portion of the rope 90 extends through a transversely apertured pull handle 98 and is knotted at a position, depending upon the position of the telescopic adjustment of the handle parts 82 and 84, of convenient access to the operator.

It will be noted that the operation of the clamping assembly 72 is such that during the telescopic extension of the handle part 82 with respect to the handle part 84, no positive means is provided for preventing the handle part 82 from being moved completely out of the part 84. In order to permit the operator to conveniently effect full extension without the inconvenience of removal, the exterior surface of the inner end portion of the handle part 82 is provided with suitable visual indicia, such as a colored coating or the like, which will provide the operator with a visual indication that full extension has been effected. In addition, as shown in FIG. 1, rope 90 has a knot 102 tied therein in a position to engage the guide pulley 82 when the handle part 62 reaches full extension, providing the operator with a further indicia of full extension which can be felt, by virtue of the fact that further extension will effect movement of the cutting head against the action of spring 24.

It will be noted that pulley assembly 96 includes the usual pulley, which like the guide pulley 82 is preferably made of nylon or the like, journaled in a riveted frame structure. As shown, the frame structure is preferably pivoted, as by a pivot pin 104, to the free end of the lever arm portion 48 so as to permit the same to be moved from the normal operative position in a counterclockwise direction as viewed in FIG. 1 into a packaging position. This capability materially reduces the size and cost of packaging and shipping the present pole pruner 10. A stop pin 106 is provided on the riveted frame of the assembly 96 for retaining the same in its operative position by engagement thereof with the adjacent edge of the lever arm portion 48. It will be noted that the tension of the rope 90 will maintain the stop pin 106 in such engagement throughout the movement of the movable member 20 between its two limiting positions.

The above described construction of the pole pruner 10 is preferred when the handle assembly 12 thereof provides for telescopic adjustment. It will be understood, however, that the aforesaid principles of the cutting head 14 of the present invention may be utilized with other types of handle assemblies including a onepiece handle assembly, if desired. FIGS. 7-9 illustrate the cooperation of the cutting head 14 with a two-piece handle assembly 12' which is of generally conventional construction. As shown, the handle assembly 12' includes a pair of handle parts 108 and 110 made of wood in conventional fashion. In this embodiment, the end portion 26 of the cutting head 14 is detachably fixedly connected to one end of the handle part 108 which is formed with a kerf 112 to receive the same. The connection is reinforced by a pair of generally semi-cylindrically shaped metal plate members 114 mounted on the exterior of the handle part 108 on opposite sides of the kerf 112. As before, the reinforcing members, handle part and end portion are suitably apertured to receive therethrough appropriate fasteners, such as bolt assemblies 116. As before, the handle part 108 is apertured, as at 1 18, in spaced relation below the end portion 26 to receive therein the associated end portion of the rope 90.

The handle part 108 functions as a one-piece handle for pruning limbs which can be reached by the operator by grasping the free end of the handle part 108. For higher limbs, the handle part functions as a handle extension which can be detachably fixedly secured to the free end of the handle part 108. Any suitable means may be utilized to effect this connection, the embodiment shown being generally of a conventional nature. With particular reference to FIG. 9, the connecting means includes a pair of generally semicylindrically shaped outer metal clamping plates 120 and an inner split sleeve 122 also made of metal, preferably aluminum or the like, rather than steel as is preferred for the plates 120.

In assembling the joint split sleeve 122 is centered over the adjacent longitudinally aligned ends of the handle parts 108 and 110 and then the plates 120 are mounted in opposed surrounding relation to the split sleeve. The end portions of the plates 120 extend beyond the ends of te split sleeve and are apertured to register with apertures formed in the end portions of the handle parts 108 and 110 respectively. The assembly of the joint is completed by inserting and tightening a conventional bolt assembly 124 through one of the sets of registering openings and an eye bolt assembly 126 through the other set. The eye of the bolt assembly receives the rope 90 therethrough and serves a guiding function similar to the guide roller 82 when the handle assembly 12 is in its fully extended position as shown in FIG. 1.

This rope guiding function which is known in twopiece handle assemblies is considered to be particularly desirable because it serves to insure that the pull forces on the rope will be transmitted to the handle part carrying the cutting head with maximum compression and minimum bending. In the absence of the rope guide function, the operator tends to effect the pull on the rope from a position spaced laterally from the handle, thus severely increasing the transmission of bending forces to the handle. The severe transmission of bending forces to the handle in conjunction with the bending action heretofore mentioned in connection with known cutting heads have been the cause of injury to known pole pruners, and perhaps, to operators as well, in the past.

The provision of the rope guiding function in telescopically adjustable handle assembly by means of a combined rope guiding and telescopic adjustment securing assembly, such as described above and indicated at 72, is, in accordance with the principles of the present invention, a significant improvement in the telescopically adjustable handle assemblies heretofore known. In this case, the rope guiding function is retained throughout the entire extent of the telescopic adjustment provided insuring at all times against the transmission of severe bending forces to the interior telescoping handle part which could cause permanent deformation of the type severely restricting, if not preventing, the telescopic action.

This desirable safeguard is provided by a simple assembly which is of economical construction and which additionally provides for the effective securement of the two telescopically arranged handle parts in any desired position of adjustment. The rope guiding function does diminish somewhat the transmission of the maximum pull force to the cutting head which can be exerted by the operator on the rope (as compared with the aforesaid pull without guidance from a laterally, outwardly spaced position) and hence the rope guiding function can be totally effective only when the cutting head is operable without the aforesaid binding action.

The cutting head 14 of the present invention cuts up to I-% inch diameter limbs without binding with a cutting action which is from 40 percent to 78 percent easier than known commercial pole pruners. These results are achieved first because the basic cutting action is by a cutting blade portion which has an essentially single bevel construction or a nonsymmetrical cutting edge and which cooperates with a single fixed member disposed on the flat side thereof, as distinguished from double beveled cutting edges which cooperate with portions of the fixed member spaced on both sides thereof. Moreover, this improved cutting action is achieved by minimizing the thickness of the cutting blade portion and providing for the cam surface guided sliding support of the outer extremity of the cutting blade portion before the cutting action in a limb of maximum size has proceeded to the point of creating excessive bending forces on the blade portion. The straight cutting edge configuration is desirable not only because of its simplicity and economy, as compared with curved cutting edges, but because of its particular cooperation with the limb engaging surfaces. Thus, as the cutting action proceeds, the direction of cut approaches a direction which is almost aligned with the direction of the closed end of the limb engaging surfaces, thus insuring that the limb will be forced into the closed end and be severed as the cutting stroke is completed.

It thus will be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the foregoing preferred specific embodiment has been shown and described for the purpose of illustrating the functional and structural principles of this invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.

What is claimed is:

1. In a pole pruner of the type including an elongated handle, a cutting head assembly on one end of said handle including a fixed member operable to be engaged with a limb or the like and a movable member operable to be moved through a cutting stroke with relation to the limb engaged by said fixed member, a rope and pulley assembly operatively connected with said movable member and extending to the opposite end portion of said handle for effecting movement of said movable member through said cutting stroke in response to a manually effected pull, and spring means for effecting movement of said movable member through a return stroke, the improvement in said cutting head assembly which comprises said fixed member being a rigid metallic member having an end portion fixedly connected with said one end of said handle, a first intermediate portion extending generally longitudinally outwardly of said one end of said handle, a second intermediate portion extending transversely from said first intermediate portion, and a free end portion extending transversely inwardly from said second intermediate portion in spaced relation to said first intermediate portion,

said first intermediate portion including a straight limb engaging surface facing in a direction toward said free end portion, said free end portion including a limb engaging surface facing toward said first intermediate portion, said second intermediate portion having a limb engaging surface interconnecting the limb engaging surfaces of said first intermediate portion and said free end portion,

said first and second intermediate portions and said free end portion having a common planar surface intersecting the limb engaging surfaces thereof,

said movable member being a rigid metallic member including a cutting blade portion and a lever arm portion,

means for mounting said movable member on said fixed member for pivotal movement between two limiting positions about an axis extending perpendicular to the aforesaid common planar surface and disposed adjacent the juncture between said first and second intermediate portions and the juncture between said cutting blade and lever arm portions,

said cutting blade portion having a planar surface disposed in a position to slidably engage the common planar surface of said first intermediate portion and said free end portion during said cutting stroke, a straight cutting edge substantially intersecting the planar surface thereof, and bevel surface means extending from said straight cutting edge,

said straight cutting edge being disposed in substantial alignment with the straight limb engaging surface of said first intermediate portion at the initiation of said cutting stroke and extending generally at right angles thereto and in general alignment with the outermost portion of the limb engaging surface of said second intermediate portion at the completion of said cutting stroke,

the extent of said cutting blade portion from said pivotal axis being so related to the extent of said free end portion from said second intermediate portion that the outer extremity of said blade portion overlaps the outer extremity of said free end portion during the cutting stroke of said cutting blade portion when said cutting edge has reached an angular position of approximately 45 with respect to the straight limb engaging surface of said first intermediate portion,

the outer extremity of said free end portion having a cam surface thereon merging into the planar surface thereof.

2. The improvement as defined in claim 1 wherein said movable member and said fixed member are both formed from flat plate stock.

3. The improvement as defined in claim 2 wherein said cam surface is provided by bending the outer extremity of said free end portion in a direction away from the planar surface of said cutting blade portion.

4. The improvement as defined in claim 3 wherein said bevel surface means includes first straight double bevel surfaces, each extending from said cutting edge at an angle of approximately 45 with respect to a plane intersecting said cutting edge and extending parallel to the planar surface of said cutting blade portion and a second straight bevel surface extending from one of said first bevel surfaces to the surface of said cutting blade portion opposite the planar surface thereof at an angle to the latter of approximately 6 5. The improvement as defined in claim 4 wherein said cutting blade portion is coated with Teflon.

6. The improvement as defined in claim 5 wherein the entire exterior of the movable member is coated with Teflon.

7. The improvement as defined in claim 2 wherein the limb engaging surface of said second intermediate portion is arcuate about a single axis and interconnects tangentially with the limb engaging surfaces of said first intermediate portion and said free end portion.

8. The improvement as defined in claim 7 wherein the limb engaging surface of said free end portion is straight and diverges toward the outer extremity thereof at an angle of approximately 16 with respect to the limb engaging surface of said first intermediate portion.

9. Theimprovement as defined in claim 1 including a pruning saw and means for detachably fixedly securing said pruning saw to said second intermediate portion in generally longitudinally outwardly extending relation therewith.

10. In a pole pruner of the type including an elongated telescopic handle assembly, a cutting head assembly on one end of said handle assembly including a fixed member operable to be engated with a limb or the like and a movable member operable to be moved through a cutting stroke with relation to the limb engaged by said fixed member, a rope and pulley assembly operatively connected with said movable member and extending to the opposite end portion of said handle assembly for effecting movement of said movable member through said cutting stroke in response to a manually effected pull, and spring means for effecting movement of said movable member through a return stroke, the improvement in said telescopic handle assembly which comprises a first tubular handle part, a second tubular handle part telescopically mounted within said first handle part and extending outwardly from one end thereof, and a combined handle part securing and rope guiding assembly including securing means fixedly secured to the exterior periphery of the one end of said first handle part and releasably fixedly connected with the exterior periphery of the portion of said second handle part extending outwardly thereof for releasably fixedly securing said second handle part with respect to said first handle part in any desired position of telescopic adjustment, and guiding means for receiving and guiding the portion of the rope of said rope and pulley assembly extending to the opposite end portion of said handle assembly.

11. The improvement as defined in claim 10, wherein said rope portion is formed with a knot at a position to engage said guide means when said second handle part is moved into a fully extended position of telescopic adjustment with respect to said first handle part providing the operator with indicia of the relative telescopic position of said handle parts so as to prevent disengagement of said second handle part from said first handle part.

12. The improvement as defined in claim 11, wherein the exterior surface of said second handle part adjacent the portion extending from the one end of said first handle part when said second handle part is in a fully extended position of telescopic adjustment is provided with color indicia.

13. The improvement as defined in claim 10, wherein said securing means includes a pair of cooperating clamping plates, each comprising a pair of longitudinally spaced generally semi-cylindrically shaped central portions, fastener receiving tab portions extending from one end of each central portion, and an integral portion extending from the opposite ends of said cen- "tral portions, means retaining said integral portions in spaced relation on one side of said handle parts, first fastener means carried by one cooperating pair of fastener receiving tab portions for releasably fixedly securing the associated central portions in friction tight engagement to said exterior periphery of said first handle part, and second fastener means carried by the tween said integral portions.

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Classifications
U.S. Classification30/249, 16/429, 16/DIG.250
International ClassificationA01G3/08
Cooperative ClassificationA01G3/08, Y10S16/25
European ClassificationA01G3/08
Legal Events
DateCodeEventDescription
Jan 28, 1982AS02Assignment of assignor's interest
Owner name: MCDONOUGH CO., A CORP. OF DE
Owner name: O. AMES CO., PARKERSBURG, WEST VA A CORP.OF DE
Effective date: 19820121
Jan 28, 1982ASAssignment
Owner name: O. AMES CO., PARKERSBURG, WEST VA A CORP.OF DE
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:MCDONOUGH CO., A CORP. OF DE;REEL/FRAME:003946/0371
Effective date: 19820121