TREE CLIMBING STICK ASSEMBLY AND METHOD OF MANUFACTURE

Abstract

A tree climbing stick includes a tubular post having upper and lower end portions. Upper and lower standoff-step components include mounting collars which are disposed about the upper and lower end portions. Retaining plugs are disposed into the upper and lower end portions opposite the mounting collars and support the end portions and cooperate to prevent the end portions from moving inward or outward to maintain a tight fit of the joint in use when subjecting to bending loads.

Claims

1. A tree climbing stick assembly, comprising: a central post fabricated of tubular material that is resiliently flexible under a bending load; at least one step supported on an end portion of the central tubular post; and at least one stabilizing member disposed within the central tubular post in position to support an inner wall of the end portion against inward flexing under the bending load.

2. The assembly of claim 1, wherein the at least one step includes a mounting collar disposed radially opposite the stabilizing member.

3. The assembly of claim 2, wherein the stabilizing member comprises at least one plug formed as a separate piece from the at least one collar.

4. The assembly of claim 3, wherein the plug has a hoop strength that is greater than a hoop strength of the end portion of the tubular post.

5. The assembly of claim 3, wherein the at least one plug has an insertion end and an exposed end, and wherein a slot extends from the insertion end and terminates short of the exposed end.

6. The assembly of claim 5, wherein the slot registers with a cross pin within the at least one end portion.

7. The assembly of claim 3, wherein the at least one plug includes indicia on an exposed end.

8. The assembly of claim 3, wherein the at least one plug supports the end portion along a full length of the at least one collar.

9. The assembly of claim 5, wherein the at least one plug has a chamfer at the insertion end interrupted by the slot.

10. The assembly of claim 3, wherein the tube is fabricated of titanium, aluminum, magnesium, steel, fiber-reinforced resin or carbon fiber.

11. The assembly of claim 3, wherein the at least one step comprises a set of upper steps adjacent an upper end of the post and a set of lower steps adjacent a lower end of the post.

12. The assembly of claim 3, wherein the plug includes outer grooves.

13. A tree climbing stick, comprising: a central post fabricated of titanium-alloy tubing extending between upper and lower ends; upper and lower standoff-step components each having a mounting collar mounted about upper and lower end portions of the post; a cross pin extending through each of the mounting collars and end portions; and a stabilizing plug disposed into each end portion to pin each end portion between the associated stabilizing plug and collar and to support each end portion against flexing within the associated collars.

14. The tree climbing stick of claim 13, wherein the stabilizing plug of each end portion includes an inserted end and an exposed end and a slot extending from the inserted end toward the exposed end and registered with the cross pin.

15. The tree climbing stick of clam 14, wherein the inserted end includes a chamfer and the exposed end includes indicia.

16. A method of reinforcing a tree climbing stick that has a flexible tubular central post with steps mounted on upper and lower end portions of the post by mounting collars and cross pins passing through the mounting collars and end portions, wherein the improvement comprises: aligning a slot on a bottom of each of two reinforcement plugs with the cross pin on each of the respective upper and lower end portions and forcibly.

17. The method of claim 16, including providing indicia on an exposed end of the plugs that is oriented relative to the slots.

18. The method of claim 17, including providing a chamfer on an insertion end of the plugs.

19. The method of claim 16, including applying a bonding agent at the interface of the plugs and end portions.

20. The method of claim 16, wherein the plugs are inserted to a depth where they do not extend longitudinally beyond the collars.

21. The method of claim 16, wherein the plugs is solid in cross section between the exposed end the slot.

Description

THE DRAWINGS

[0012] This and other features and advantages will become better understood when considered in connection with the detailed description and appended drawings, in which:

[0013] FIG. 1 is a perspective view prior art tree climbing stick;

[0014] FIG. 2 is a fragmentary cross-sectional view of the upper prior art joint of FIG. 1 shown with an exaggerated tilt of the steps under a bending load;

[0015] FIG. 3 is an enlarged fragmentary end view of the prior art joint of FIG. 2 looking in the direction of arrows 2-2 showing the wall of the tube flexed inwardly of the collar under the bending load;

[0016] FIG. 4 is a perspective view of a tree climbing stick according to a preferred embodiment shown secured to a tree;

[0017] FIG. 5 is a top view of the tree climbing stick of FIG. 4;

[0018] FIG. 6 is an enlarged isometric view of a stabilizing plug according to an embodiment;

[0019] FIG. 7 is an enlarged fragmentary longitudinal cross-sectional of the collar-tube-plug joint shown under a bending load;

[0020] FIG. 8 is a cross-sectional view taken along lines 8-8 of FIG. 7 shown under a bending load;

[0021] FIG. 9 is a cross-sectional view taken along lines 9-9 of FIG. 7 shown under a bending load;

[0022] FIG. 10 is a series of enlarged schematic cross-sectional views showing the sequence of shaping and supporting the tubular post to conform to the outer and inner shapes of the collar and stabilizing plug of the joint;

[0023] FIG. 11 is an enlarged fragmentary cross-sectional view of an alternative embodiment;

[0024] FIG. 12 as an enlarged fragmentary cross-sectional view of another alternative embodiment;

[0025] FIG. 13 is an isometric view of an alternative stabilizing plug; and

[0026] FIG. 14 is an isometric view of an alternative stabilizing plug.

DETAILED DESCRIPTION

[0027] FIG. 4 illustrates an embodiment of tree climbing stick, or climbing stick 30. The climbing stick 30 includes a main or central post 32 that extends longitudinally between opposite ends 34, 36. The post 32 is tubular in construction and includes open-ended tubular end portions 38, 40 adjacent the post ends 34, 36, respectfully.

[0028] The tubing of the post 32 may be made of metal such as steel, aluminum, titanium, magnesium, etc., or it may be made of a non-metallic material such as carbon fiber tubing. It will be understood that reference to tubing materials or that of other components includes alloys of these materials, such that reference to a titanium, steel, magnesium or aluminum tube or component encompasses their alloys.

[0029] The wall thickness of the tubing 32 is selected to provide sufficient strength to the post 12 to support the weight of a user that may impart various loads and stresses on the post 32. The material selection and wall thickness of the tube 32 may also be factored by the desire to produce a light weight climbing stick 30, for example one with a total weight of 1 pound or less. These various factors may yield a tubular post 32 that is sufficiently strong to support the weight of the user, but nonetheless may elastically bend and flex under load in various ways depending on how the forces are applied. As such, it is contemplated that the wall of the tubing may be strong and stiff, but yet flexible, such that the wall of the tube may tend to flex inwardly or outwardly including at the end portions 38, 40, and the post 32 may bend and flex intermediate its ends 34, 36. Thin-walled titanium alloy tubing is such a material, including Grade 9 TA-18, Ti-3 Al-2.5V tubing which may be a preferred material. It has a very high strength-to-weight ratio relative to steel or aluminum. It is very light weight (40% lighter than steel), very strong (twice as strong as aluminum) and very durable. Even so, such thin-walled titanium tubes flex under the compression and bending loads when used as the post for a climbing stick. Thin-walled steel and aluminum may also flex, as may other materials including carbon fiber tubes. By thin-walled, it is meant that the material and wall thickness of the tube is sufficiently strong to support the weight of the user and the loads and forces applied to the tube during extended use, but with attention also to weight minimization in an effort to produce a strong but light weight climbing stick. For example, and according to a preferred embodiment, a length of Grade 9 TA-18 titanium tubing may be used having a length of about 457 mm with a nominal outer diameter of 25.4 mm and a nominal inner diameter of 24.6 mm, yielding a nominal wall thickness of about 0.9 mm.

[0030] An additional challenge with light-weight, thin-walled tubing materials, such as titanium, is that the manufacturing tolerances of commercially available product are not true to shape. In other words, round titanium tubing is typically not perfectly round and may actually be significantly out-of-round so it tends toward oval. In the above example, the 25.4 mm OD and 24.6 mm ID represent an average, when in fact there are likely irregularities or variations about the circumference. The wall thickness is generally uniform, but there may be slight variations in surface texture due to manufacturing (e.g., die lines from extrusion). Steel, aluminum and carbon fiber tubing may experience similar shape discrepancies. While various cross-sectional shapes of the post 32 are contemplated (e.g., round, square, rectangular, hexagonal, etc.) round or circular is preferred as it yields the least amount of material and lends to reduced weight and cost. The misshapen tubing tends to be generally uniform along its length, such that the end portions 38, 40 may be similarly misshapen prior to assembly with the other components to be described.

[0031] The climbing stick 30 further includes at least one step 42 preferably located adjacent one of its ends 34, 36. It is more preferred that there are at least two steps 42, 44 and that an upper one 42 of the steps is provided adjacent the upper end 34 of the post 32, and that a lower one 44 of the steps is provided adjacent the lower end 36. It is still further preferred that the upper and lower steps 42, 44 each have left and right foot pads projecting from laterally opposite sides of the post 32 and denoted in the Figures as 42a, 42b and 44a, 44b, respectively.

[0032] The climbing stick 30 further includes at least one and preferably two tree braces or standoffs 46, 48 provided adjacent the upper and lower ends 34, 36 of the post 32, respectively. The standoffs 46, 48 may be separate structures from that of the steps 42, 44 or, as illustrated, may be combined as a single structure with each of the steps 42, 44 to yield upper and lower standoff-step components 50, 52.

[0033] The at least one step 42 is provided with a mounting collar 54 for attachment to the post 12. More preferably each of the standoff-step components 50, 52 are mounted to the post via respective collars 54, 56. Still more preferably, each of the upper and lower standoff-step components 50, 52 includes as part of its unified structure the collar 54, 56, respectively, for mounting to the post 32. The unified components 50, 52, including the collar portions 54, 56 may be fabricated of a suitable light-weight material such as aluminum and may be precision machined. As illustrated, the collars 54, 56 may be disposed between and join the respective left and right foot pads 42a, 42b and 44a, 44b. The standoffs 46, 48 may each have left and right portions, denoted 46a, 46b and 48a, 48b that project from a backside of the footpads 42a, 42b and 44a, 44b, respectively, and may further engage the collars 54, 56 along their inward edge. The standoffs 46, 48 present rearward-facing jaws 58 that face away and are spaced laterally from the steps 42, 44 and post 32 to define generally V-shaped cradles or braces adjacent the ends 34, 36 of the post 32 for engaging the trunk of a tree and supporting the post 32 and steps 42, 44 and collars 54, 56 in outwardly spaced relation to the tree.

[0034] The collars 54, 56 are mounted on the end portions 38, 40 of the post 32. More specifically, the collars 54, 56 are each formed with a bore 60 for receiving the respective end portion 38, 40 into the bore 60. Even more preferably, the ID of bore 60 is dimensioned relative to the OD of the end portions 38, 40 so that the end portions 38, 40 are received with a close fit, and preferably a press fit. The bore 60 is preferably machined and is cylindrical in shape and with a profile that is preferably round in cross section. The collars 54, 56 may be the same length as the thickness of the steps 42, 44 where they join the collars 54, 56. The size of the bores 60 may further take into account the out-of-roundness of the tubing material at the end portions 38, 40 and in achieving the pressfit also reshape the wall of the tubing to conform to the round shape of the bore 60. The bore 60 may be slightly undersized relative to the nominal OD of the end portions. In the example of where the end portions have a nominal OD of about 25.4 mm, the ID of the bore 60 may be 25.3 mm, with the 0.1 mm accommodating for out-of-roundness and achieving a tight friction fit with the OD of the end portions 38, 40. A press may be used to force the collars 54, 56 onto the end portions 38, 40. Once attached, a cross pin 62 may be installed in aligned cross bores through the collars 54, 56 and end portions 38, 40 to provide added strength to the collar-tube joints including in the axial and rotational directions.

[0035] The improved climbing stick 30 further includes at least one and preferably two retention or stabilizing plugs 64 that are disposed in the open end portions 38, 40 of the post 32 as illustrated in FIGS. 6-11. The plugs 64 have an outer surface that compliments the shape of the ID of the collars 54, 56. The plugs 64 are preferably cylindrical in shape on their OD and may be formed of a suitable material such as aluminum. The complimentary cross-sectional shape may be round and is sized to engage the inner wall surface of the end portions 38, 40 with similar tight fit to that achieved on the outer surface of the end portion 38, 40 with the collars 34, 36. The OD of the plugs 64 may be slightly oversized relative to the ID of the end portion wall 38, 40. The size of the plug 64 compliments the size of the collar bores 60 (so that the end portions 38, 40 are captured or pinned firmly and immovably between the collars 54, 56 and the plugs 64, preferably with a pressfit connection on both the OD and ID of the end portions 38, 40. This is illustrated in FIGS. 7-9. In the example where the nominal ID of the end portion is 24.6 mm, the OD of the plug may have a dimension of 24.7 mm, with the 0.1 mm accommodating for out-of-roundness of the ID of the end portions 38, 40 and achieving a tight friction fit with the ID of the end portions 38, 40. The plugs 64 are sized and shaped to effectively shape the wall of the end portions 38, 40 from the inside so the wall conforms to the cylindrical shape of the plugs 64 on the inside and to the cylindrical shape of the collar bores 60 on the outside, and both with a tight fit. A press may be used to force the plugs 64 into the end portions 38, 40. FIG. 10 illustrates the sequence of pressing the out-of-round tube 32 into the round bore 60 of the collar 52, 54, followed by pressing the plug 64 into the end of the tube 32 to reshape the tube wall into tight conformance with both the plug 64 and collar bore wall 60. The end portions 38, 40 are thus firmly pinned between the plugs 64 and on the outside by the collars 54, 56 and the plugs 64 support the end portions 38, 40 from flexing inwardly and loosening from the collars 54, 56. The improved climbing stick 30 with plugs 64 may also create an air-free environment or retaining compounds to further strengthen the connections at the joints. Grooves or other pockets or features can also be added to the surfaces of the bores 60 and plugs 64 to accommodate air-curable adhesive without detriment to the fit and integrity of the press-fitted joints. FIG. 14 illustrates such an alternative plug 64″′ wherein the outer surface is provided with shallow grooves 65 that are sized to create optimal conditions for a selected binding agent, both as to clearance and surface area, between the plug 64″′ and the inner wall of the tube 30 in which it is pressed. The number, size and pattern of the grooves 65 may vary depending upon the requirements of a given application. The plug 64″′ may be used in place of plug 64 and may or may not be used in conjunction with a cross pin 62.

[0036] The plugs 64 extend axially between an insertion end 66 and an exposed end 68. The plug 64 is preferably solid in cross section over at least part of the length of the collars 54, 56 and more preferably adjacent the insertion end 66. Alternatively, the plugs 64 may be cylindrical but with walls of sufficient thickness, strength and integrity (i.e., hoop strength) to resist any inward flexing of the end portion walls 38, 40 away from the collars 54, 56 that would loosen the joint.

[0037] As illustrated in 6, 7 and 9, the plugs 64 may be formed as a separate piece from the collars 54, 56. The plugs 64 may be precision machined from aluminum or other suitable material into a cylindrical shape and may include a chamfer or taper 70 at the insertion end 66 for guidance into and along the open end portions 38, 40 of the post 32. The plugs 64 may be the same length or longer than the length of the collars 54, 56 so that they provide support to the end portions 38, 40 over the full length of the collars 54, 56.

[0038] The plugs 64 may further include a cross slot 72 that is open at the insertion end and extending toward the exposed end 68. The cross slot 72 is sized and positioned to receive the cross pin 62 into the slot 72 when the plug 54 is pressed into the respective end portion 38, 40. The slot-to-pin registration further acts to orient the face of the exposed plug end 68 in an exact rotational orientation relative to the cross pin 62. The exposed end 68 of the plug 64 is preferably solid. The exposed end 68 may reside outside of the tube ends 34, 36, but is preferably pressed to be flush or even with the ends 34, 36 so that the plugs 64 are full pressed into and even with the edges of the end portions 38, 40. Advertising indicia 74 such as a company name logo or other information may be provided on the exposed end face 68 and aligned in position relative to the cross pin 62 so that is appears in the same repeatable orientation from product to product. For example, when looking face on to the installed plug 64, the indicia 74 may extend perpendicular to the cross pin 62 or be repeatedly oriented relative to another feature of the assembly. The portions of the plug 64 that extend around and past the pin 62 firmly engage the ID of the end portion in the same manner as the solid portion of the plug 64 above the pin 62. Alternatively, the plug may be solid end-to-end and contain a cross bore instead of a slot, in which case the plug is installed before installation of the pin which is received through the aligned bores of the collar, end portion wall and plug.

[0039] The orientation of the cross pin 62 and cross bores may be arranged at any orientation relative to the axis of the steps 42, 44, such as perpendicular, as illustrated, parallel, or somewhere in between.

[0040] The climbing stick 30 further includes at least one attachment bracket 78 for engaging a rope, cable or strap for removably securing the climbing stick 30 to a tree.

[0041] A method of making the climbing stick 30 includes obtaining a length of tubular post 32 material. The collars 54, 56 of the top and bottom components 50, 52 are pressed onto top and bottom end portions 38, 40 of the post 32. The cross pins 62 are installed in the cross bores drilled through the collars 54, 56 and end portions 38, 40. The plugs 64 are pressed into the open ends 34, 36 of the end portions 38, 40 and straddle the cross pins 62 which are received into the slots 72. The plugs 64 close off the open ends of the end portions 38, 40 and support the wall of the end portions 38, 40 from flexing or moving inwardly away from the collars 54, 56. FIG. 11 is a fragmentary top view of the climbing stick 30 with the plug 64 shown sectioned for emphasis. FIG. 11 is a comparable view to the FIG. 3 prior art stick 10, with both showing the sticks 10, 30 under a heavy bending load as was illustrated and described in connection with FIG. 2. N this state, a person may be standing on the upper right-hand step 42 and imparting a concentrated bending load at the collar joint. Unlike FIGS. 2 and 3 of the prior art stick 10, where the wall of the tube flexes inwardly away from the collar and forms a gap 29, the plug 64 of the stick 30 according to the embodiment supports the inside wall of the tube 32 against such inward flexion, keeping the outer surface of the tube 32 tight against the wall of the collar bore 60 and also tight against the outer surface of the plug 64, thereby stabilizing the joint against compromise in the presence of side-to-side bending loads and other forces that may otherwise loosen the tight connection between the collars 54, 56 and tube ends 38, 40. The plug 64 receives and distributes the concentrated bending load that would otherwise cause inward flexing to other parts of the tube, keeping the integrity of the joint intact.

[0042] It is contemplated that one may wish to retrofit an existing stick with the reinforcing members 64 into order to prevent loosening of the joints or to stabilize joints that have already been compromised. In such case, one would align the plugs 64 and press or lightly tap the plugs 64 into each open end portion 54, 56, which will tighten the joints and prevent inward flexing of the tube wall within the joint.

[0043] FIG. 12 illustrates an alternative embodiment of a climbing stick 30′ which may be the same as that described above in connection with embodiment 30 and the features thereof incorporated herein by reference and their corresponding reference characters primed. In the alternative embodiment, the collars 54′, 56′ and plugs 64′ are formed as a single piece rather than separately, defining a circumferential groove 80 between the collar 54′, 56′ and plug 64′ portions into which the end portions 38′, 40′ are pressfit. A cross pin 62′ may be pressed into a cross bore drilled through the collars 54′, 56′, the end portions 38′, 40′ and the plugs 64′ if desired.

[0044] FIG. 13 illustrates another embodiment of a climbing stick 30″, wherein the same reference numerals will be used to represent like parts but denoted by double-prime. The stick 30″ includes a similar flexible wall tubular post 32″ having end portion 54″, 56″ to which steps 42′, 44′ are mounted and secured by a fastener 82, such as a threaded bolt and nut, passing through a corresponding opening 84 in the end portion 54″, 56″. A plug 64″ is pressed into the end portions 54″, 56″ and is provided with an opening 86 that aligns with opening 84 to receive the fastener 82. There may be a single step on the right or left side, or there may be pairs of left and right steps, as illustrated, in each of the upper and lower locations. Where left and right steps are provided, the same fastener 82 may be used to attach both. The right and left steps may be separate parts or unified as a single structure. The fastener stud 82 may be a separate piece from that of the steps 42″, 44″or it may be unified as a threaded post.

[0045] In use, a person wishing to scale a tree orients the post 32 vertically and cradles the tree in the jaws 58 of the standoffs 46, 48. The strap, rope or cable is extended around the tree and the ends cinched tight and secured to the attachment bracket 76. The user may then climb the stick 30 and repeat the process by placing and securing additional climbing sticks 30 until the desired height is achieved. The weight placed on the steps 42, 44 by the user is transferred to the collars 54, 56 and to the post 32, and the post 32 might bend and flex, but not within the upper and lower collar-plug joints, which are isolated from such flexing and stress by the tight fit of the plugs 64 and collars 54, 56 to the inside and outside of the end portion wall 38, 40. Extended use of the improved climbing stick 30 is possible without loosening of the collar-plug joints.

[0046] It is to be understood that the invention may be practiced otherwise than as specifically described while still being within the scope of the invention. The invention is defined by the appended claims.