Apparatus for holding substantially cylindrically shaped elements

A self-adjusting apparatus is provided for clamping and supporting a substantially cylindrical element. When an element is placed in the self-adjusting apparatus, the element is supported at about 90° from the surface on which the apparatus sits. This is achieved with an integrated clamping mechanism and, preferably, with a self-centering mechanism comprising flexure springs and a retaining-center pin. The clamping mechanism applies a substantially radial force on the element that is directly proportional to the substantially cylindrical element's weight, and can be less than the weight of the element, preventing damage to the element. The present invention can include a liquid management system for when the apparatus supports a tree trunk. The liquid management system can include a reservoir, a funnel for filling the reservoir, a capillary wick and mat that provides water to the tree even when it is above the level of water in the reservoir.

FIELD OF THE INVENTION

The present invention relates generally to an apparatus to support substantially cylindrical elements in a substantially vertical position. More particularly, the present invention relates to a self-adjusting apparatus for supporting a substantially cylindrical element, such as a cut tree, in a substantially vertical position.

BACKGROUND OF THE INVENTION

Stands for supporting trees and other substantially cylindrical elements are known in the art and numerous examples show the complexity of the mechanisms used to clamp and support a substantially cylindrical element. The mechanisms are varied, but are typically inconvenient as they require the user to crouch, kneel or lie on the ground and tighten the clamps at the same time as the user holds the element in a vertical position. Often, a second user is required to hold the element in a substantially vertical position while the first user tightens the clamps.

Some known approaches use the weight of the element to create a clamping force that is present as long as the element is in the apparatus. For example, U.S. Pat. No. 2,464,593 (Lorenzen) describes a tree holder in which the weight of the tree rests on a spring-supported conical cup, or retaining member. The displacement of the cup due to the weight of the tree causes knife-edge gripping blades to pivotally engage the tree trunk. U.S. Pat. No. 3,301,512 (Nyberg) describes a stand in which the weight of the element on a retaining member causes movable clamping arms to pivot and engage the tree trunk. U.S. Pat. No. 4,007,901 (Mancini) also describes a tree stand in which the weight of the element in a central reservoir, or retaining member, causes the legs to pivot and engage clamping arms with the tree trunk. Finally, U.S. Pat. No. 6,661,519 (Cone) describes an apparatus in which clamping arms pivot to engage a tree in response to the weight of the tree placed in a centrally disposed reservoir or retaining member.

In the references noted above, each apparatus describes the clamping arms as pivoting towards the tree trunk. The '519 patent to Cone further describes a locking mechanism to lock the clamping arms to the tree trunk. Each clamping mechanism is prevented from disengaging the tree trunk by the force generated by the weight of the tree on the retaining member. The force is transmitted to the tree trunk through the clamping arms pivoting on a fulcrum and engaging with the tree trunk. For a given weight of an element, the force applied by a pivoting clamping arm on the element depends on the diameter of the element, with large diameter elements experiencing greater applied forces than smaller diameter elements. This non-constant application of force on the element is a function of the amount of displacement of the clamping arms, and can damage the substantially cylindrical element being held.

It is therefore desirable to provide an apparatus with improved force characteristics to hold a substantially cylindrical element.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved apparatus which overcomes one or more deficiencies found in the prior art.

In an embodiment, the present invention provides a self-adjusting apparatus for holding a substantially cylindrical element in a substantially vertical position with respect to a surface of reference. The self-adjusting apparatus has a base for placement on the surface of reference and a receiving chamber attached to and extending upwardly from the base to define a receiving area for receiving the substantially cylindrical element. The receiving chamber defines an opening. The apparatus includes a retaining member for retaining a lower portion of the substantially cylindrical element within the receiving area. The retaining member is disposed within the receiving area and below the opening. The retaining member is vertically movable in response to receiving the substantially cylindrical element. The apparatus has a plurality of clamping mechanisms, each clamping mechanism coupled to the receiving chamber. Each clamping mechanism has a clamping arm moveable along a radial axis, the axis being below the opening and above the retaining member. The clamping mechanism has a cable system operatively connecting the clamping arm to the retaining member to automatically move the clamping arm from a rest position to a clamping position in response to downward vertical displacement of the retaining member. The apparatus clamps the substantially cylindrical element in the substantially vertical position.

In the absence of an externally applied force, the clamping arm can exert a clamping force on the substantially cylindrical element that is directly proportional to the weight of the substantially cylindrical element. In some embodiments, for a given weight of the element and in the absence of any externally applied force, the clamping arm can exert a substantially constant clamping force on the substantially cylindrical element irrespective of the clamping position. The clamping force can be less than or equal to a downward force due to the weight of the substantially cylindrical element on the retaining member. The clamping force can be between about 0.002 and about 0.6 times the weight of the substantially cylindrical element on the retaining member.

The clamping mechanism can include two cooperating elements which exert a variable frictional force on each other in order to prevent the clamping mechanism from unclamping in response to a substantially horizontal external force applied to the substantially cylindrical element.

The clamping arm can be a threaded clamping arm and the clamping mechanism can also includes a threaded cylinder. In such an apparatus, the frictional force is between the threaded clamping arm and the threaded cylinder. When the frictional force is between the threaded clamping arm and the threaded cylinder, the cable system includes a cable under tension and the frictional force can prevent the external force from affecting the magnitude of tension in the cable.

The clamping arm can be an unthreaded clamping arm and the cable system can also include a cable and a fixed pulley. In such an apparatus, the frictional force is between the cable and the fixed pulley. When the unthreaded clamping arm and cable system have a cable and fixed pulley, the cable system can include a first tension (T1) in the portion of the cable between the unthreaded clamping arm and the fixed pulley; a second tension (T2) in the portion of the cable between the fixed pulley and the retaining member; and the ratio between the first tension and second tension (T1/T2) can be between about 0.08 and about 0.00008.

The clamping mechanism can include a geared transmission to achieve a desired amount of radial displacement of the clamping arm as a function of the amount of vertical displacement of the retaining member. When the clamping arm includes a geared transmission, the desired amount of radial displacement of the clamping arm can be between about 0.8 and about 1.2 times the vertical displacement of the retaining member.

The self-adjusting apparatus can have a flexure spring mechanism attached to the retaining member to center the substantially cylindrical element within the opening. The flexure spring mechanism can have a single ring-type member, or at least two flexure springs. The retaining member can further include a center pin located substantially in the center of the retaining member.

The clamping arms can be radially spaced substantially equally around the perimeter of the receiving chamber. The clamping arms can define a substantially circular opening whose radius is greater than the radius of the substantially cylindrical element. Embodiments of the apparatus can have three, four, or more clamping arms.

The self-adjusting apparatus can have a liquid management system when the substantially cylindrical element is a tree. The liquid management system can include a reservoir disposed below the opening and within the receiving area. The liquid management system can also have a funnel in liquid communication with the reservoir for filling the reservoir with liquid. The liquid management system can also have a means for indicating the level of liquid in the reservoir.

The liquid management system can have a capillary system for drawing liquid from a lower portion of the reservoir up to a portion of the reservoir above the retaining member when the level of liquid in the reservoir is below the retaining member.

In yet another embodiment, the present invention provides an self-adjusting apparatus with a plurality of posts. The posts are attached to and extending upwardly from the base. The posts define a receiving area for receiving the substantially cylindrical element, the receiving area defining an opening between upper ends of the plurality of posts. The clamping mechanisms are coupled to one of the plurality of posts.

When the apparatus has a plurality of posts, the number of clamping mechanisms can be equal to the number of posts, and each post can have one clamping mechanism coupled thereto. Each clamping arm can be integral with the post to which it is coupled. The plurality of posts can be integral with the receiving chamber.

In yet another embodiment, the present invention provides a self-adjusting apparatus where the clamping mechanism is operably connected to the retaining member and moves along a radial axis in response to downward vertical displacement of the retaining member.

The apparatus can be for holding a tree trunk. The tree trunk being held is often the tree trunk of a tree used for hanging decorations thereon, such as a Christmas tree.

DETAILED DESCRIPTION

The terms “substantially cylindrical shaped element” and “substantially cylindrical element” are used interchangeably herein to represent a tree trunk, a branch, a pole, an umbrella, a coat tree, a coat peg or any other object having a substantially cylindrical shape, a slightly conical shape or any variant of these, etc. The term “tree trunk” can represent the trunk of a tree, a shrub, or any other living plant or tree.

The term “cable” is understood to be a row or string of elements united by, or as if by, braiding, twisting, twining or threading, and is also used herein to represent a chain; wire; rope; line; band; ribbon; strip; a slender, flexible, rod or narrow sheet; or any variant of these. In more mechanical terms, the term “cable” herein designates a component that exhibits relatively high stiffness when subjected to tension loads and relatively low stiffness when subjected to flexion loads. This characteristic implies that the component can be easily wound but is hard to stretch or elongate.

A new substantially cylindrical element supporter has been designed with the aim of improving the force characteristics exerted on the element by the self-adjusting apparatus of the present invention. The clamping force exerted by the clamping arm on the element can be directly proportional to the weight of the substantially cylindrical element.

The term “radial axis” is herein defined as an axis being substantially perpendicular to the substantially vertical center axis of a receiving area for receiving the substantially cylindrical element. Therefore, radial displacement is translational displacement along the radial axis and radial force is a force exerted along the radial axis.

The new substantially cylindrical element supporter has also been designed with the aim of modulating the force exerted on the element by the self-adjusting apparatus of the present invention. Self-adjusting apparatuses employing clamping arms with force amplifiers, using mechanical advantage such as pivots and fulcrums, can damage the elements to be supported. In the self-adjusting apparatus of the present invention, the magnitude of the force exerted by the clamping arm can be reduced.

Further, apparatuses of the present invention reduce the hassle related with the use of other products on the market today. With embodiments of the present invention, there is no need for the user to bend down or to get on his/her knees to clamp the apparatus to the substantially cylindrical element or to refill it, etc.

An apparatus according to embodiments of the present invention can be provided for residential, commercial or industrial uses where it is desirable to clamp and support a substantially cylindrical element in a substantially vertical position.

Generally, the present invention provides a self-adjusting apparatus for clamping and supporting a substantially cylindrical element. When an element is placed in the self-adjusting apparatus, the element is supported at about 90° from the surface on which the apparatus sits. This is achieved with an integrated clamping mechanism and, preferably, with a self-centering mechanism comprising flexure springs and a retaining-center pin. The clamping mechanism applies a substantially radial force on the element that is directly proportional to the substantially cylindrical element's weight, and can be less than the weight of the element, preventing damage to the element. The present invention can include a liquid management system for when the apparatus supports a tree trunk. The liquid management system can include a reservoir, a funnel for filling the reservoir, a capillary wick and mat that provides water to the tree even when it is above the level of water in the reservoir.

PARTS IDENTIFICATION

1Substantially cylindrical element10Self-adjusting apparatus of the first embodiment12Clamping mechanism14Post of the first embodiment16Base of the first embodiment18Threaded clamping arm20Retaining member22Clamping cable24Rewinding cable26Pulley28Cable end fitting30Recall spring32Ring gear34Shell of the first embodiment36Leg of the first embodiment38Foot of the first embodiment40Reservoir42Funnel44Capillary mat46Capillary wick48Capillary mat and wick combination50Capillary mat spring5290° hose plug54Indexing groove56Clamping arm stopper58Cap60Indexing pin62First stage sun gear and second stage planet carrier64First stage planet gear66First stage planet carrier68Second stage sun gear and third stage planet carrier70Third stage sun gear72Second stage planet gear74Third stage planet gear76Threaded cylinder78Self-adjusting apparatus of the second embodiment80Clamping mechanism of the second embodiment82Post of the second embodiment84Base of the second embodiment86Un-threaded clamping arm88Shell of the second embodiment90Leg of the second embodiment92Foot of the second embodiment94Funnel holder96Return spring98Fixed pulley100Un-threaded clamping arm guide102Flexure spring104Gliders106Small rod108Retaining member center pin

FIG. 1illustrates a first embodiment of a self-adjusting apparatus10including a clamping mechanism12for holding a substantially cylindrical element1(shown inFIG. 15). A receiving chamber extends upwardly from base16. The clamping mechanism12can be coupled to the receiving chamber. The clamping mechanism12of the embodiment illustrated inFIG. 1is coupled to one of a plurality of posts14. The posts inFIG. 1are attached to and extend upwardly from the base16and are integral with the receiving chamber. The clamping mechanism12can be located at the upper ends of one of the plurality of posts14, as shown inFIG. 1. In an alternative embodiment (not shown), the clamping mechanism12can be coupled to a receiving chamber that does not include a post. The receiving chamber, whether having integral posts, as illustrated inFIG. 1, or lacking posts defines a receiving area for receiving a substantially cylindrical element. The receiving chamber further defines an opening at an upper edge thereof. The receiving chamber has a diameter appropriate for receiving the diameter of a substantially cylindrical element typically used in a given application. An embodiment of the present invention can have at least one clamping mechanism coupled to the receiving chamber. The clamping mechanism12in the embodiment ofFIG. 1comprises a threaded clamping arm18or screw. A force applied to the threaded clamping arm18is imparted by the weight of the substantially cylindrical element on a retaining member20and activates the threaded clamping arm18or screw. The retaining member20is located within the receiving area of the receiving chamber and below the opening.

In an embodiment, the present invention comprises posts (each having a clamping mechanism coupled thereto) that are radially spaced substantially equally around the base member and defining an opening. The opening, for example a circular opening, has a diameter appropriate for receiving the diameter of a substantially cylindrical element typically used in a given application. In such instances, the radius of the opening can be greater than the radius of the substantially circular element. However, in another embodiment, the posts have clamping mechanisms that are spaced unequally around the base member. In that case, the clamping arms associated with the clamping mechanisms exert forces that engage the substantially cylindrical element with a post lacking a clamping mechanism. In various embodiments, the posts, both those having and those lacking clamping mechanisms, can be spatially adjustable on the base.

Although the clamping mechanisms can be coupled to fixed posts that displace a movable clamping arm, in a further embodiment the post and clamping arms are integral with one another, and the post and clamping arm are operably connected by a clamping mechanism to the retaining member. In various embodiments of the present invention, the apparatus can have three or four clamping arms. An apparatus can also have more than four clamping arms.

FIG. 2further depicts various preferred components of the self-adjusting apparatus10and clamping mechanism12of the first embodiment. Two cables, a clamping cable22and a rewinding cable24are attached to a pulley26which has two cavities to enroll the cables. The cables22and24are joined at a first end thereof to the pulley26by a cable end fitting28. In the first embodiment, the other end of each cable is a loop. The clamping cable22is joined to the retaining member20, shown inFIG. 1. The rewinding cable24connects the pulley26to a recall spring30. The rewinding cable24and recall spring30rewind the threaded clamping arm18to its starting position, or rest position, when the weight of the substantially cylindrical element1, not shown, is removed from the retaining member20, shown inFIG. 1.

In the mechanism's starting position, or rest position, the retaining member20is typically at its highest possible position. The mechanism's maximum ending position is typically the configuration in which the retaining member20is at its lowest possible position when no substantially cylindrical element is being retained. The mechanism's clamping position is typically the configuration in which the threaded clamping arm18is engaged with the substantially cylindrical element and the retaining member20is at a position between the highest and lowest possible positions. In the rest position, the clamping arm can be prevented from moving radially outward by the post to which the clamping mechanism is engaged. In another embodiment, the starting or rest position of the clamping arm can be settable such that the opening defined by the portions of the clamping arms that engage the substantially cylindrical element is different than the opening defined by the posts to which the clamping mechanisms are connected. The internal elements of clamping mechanism12rotate relative to a fixed ring gear32.

FIG. 3further illustrates an embodiment in which the self-adjusting apparatus10includes a shell34. The shell34preferably covers the functional parts of the self-adjusting apparatus. The purpose of the shell34is to allow a more esthetically pleasing look to the self-adjusting apparatus of the present invention. In other words, the shell34brings an appealing esthetic value to the present invention. Both embodiments described herein are preferably supported by a base. The base16(shown inFIG. 1) can be provided within the shell, or can be integral with the shell. In an embodiment where the base is not integral with the shell, the shell can be placed around the functional parts of the self-adjusting apparatus during a final stage of production, allowing for a variety of shells to be applied to the same functional parts of the self-adjusting apparatus to provide products of varying styles, construction and sophistication.

Since the center of mass of the substantially cylindrical element may be far from the surface of reference on which the apparatus rests, it is important to stabilize the self-adjusting apparatus that clamps the substantially cylindrical element. The self-adjusting apparatus is more stable the further the contact point(s) is (are) from the main axis of the substantially cylindrical element, as long as the center mass of the substantially cylindrical element is located somewhere along the center axis of the self-adjusting apparatus. The base16or shell34of the present invention can have one or more contact surfaces(s) with the ground. The base16or shell34can comprise at least one leg36and one foot38. The leg36and foot38can be provided as separate elements, or be provided integral with one another.

In various embodiments of the present invention, the base, foot or leg can include a fastening means to secure the base to the surface of reference. Such fastening means include bolts, screws, or any other means known in the art to removably attach the apparatus to the surface of reference.

In some cases, such as when the substantially cylindrical element is a trunk of a live tree, there is a need for the substantially cylindrical element to be nourished by a liquid, such as water.FIG. 4is a complete section view of the self-adjusting apparatus ofFIG. 3taken along the line A-A and showing elements of a liquid management system. Presently preferred components of the liquid management system can be seen inFIG. 4. The liquid management system can comprise a liquid reservoir40defining an area for holding liquid, the liquid reservoir being in liquid communication with the substantially cylindrical element. In the embodiment ofFIG. 4, the reservoir is defined by the base16, posts14, and walls connecting the base16and posts14. In the embodiment illustrated inFIG. 3, the receiving chamber is integral with the liquid reservoir40. Alternatively, the reservoir can be defined by a base and wall that are not integral with the base16or posts14.

A funnel42can make it easier for the user to fill the reservoir40with liquid. The opening of the funnel42is preferably placed away from the reservoir40. This makes it possible for the user to avoid bending down or getting on his/her knees to fill the reservoir40. The funnel42can also indicate a liquid level in the reservoir40. One line or indicator can be provided on a substantially transparent or substantially translucent funnel42to indicate the liquid level at which the reservoir is full and another line to indicate the level when the reservoir40is considered empty, or requiring extra liquid. These lines are provided so that they overlay the line naturally created by the liquid level when the funnel42is in its planned position of use.

The retaining member20, which is engaged with the substantially cylindrical element, is at a distance from the bottom of the reservoir40. This can result in a volume of liquid not contacting the substantially cylindrical element1. In the embodiment ofFIG. 4, a capillary feeding system is provided to bring liquid from the bottom of the reservoir40up to the substantially cylindrical element resting on the retaining member20. In this manner, liquid contained by the reservoir40can be brought to and absorbed by the substantially cylindrical element. This capillary system can include a capillary mat44to cover the area of the retaining member20and spread out the liquid. One or more wick(s)46, in liquid communication with the capillary mat44, bring liquid up to the capillary mat44by capillary action. The capillary wick46preferably comprises small fibers maintained one against the others. This creates small gaps between each fiber, which act like small tubes. These small tubes rely on the surface tension of the liquid to raise the liquid against gravity. A portion of the capillary wick46preferably extends to the bottom of the reservoir so that it is covered by the liquid.

The capillary feeding system can be used so that a substantially cylindrical element receives its needed liquid, no matter the diameter of the element. The capillary mat44is preferably positioned between the top of the retaining member20and the bottom of the substantially cylindrical element. In this manner, the capillary mat44can provide liquid to the substantially cylindrical element even when there is no portion of the substantially cylindrical element is submerged in the liquid in the reservoir.

A 90° hose plug52is engaged with the bottom of the reservoir40. The 90° hose plug can be self-sealing and allows the funnel42to be in liquid communication with the reservoir40. When engaged with the reservoir40, the flexible lip of the hose plug52gets pressed against the exterior surface of the reservoir's40bottom, which forms a tight seal. In an alternate embodiment, the 90° hose plug can be provided as a different type of plug performing substantially similar functions.

FIG. 5illustrates a clamping mechanism according to an embodiment of the present invention including a geared transmission A geared transmission can be used to achieve a desired radial displacement of the threaded clamping arm18in relation to the vertical displacement of the retaining member20. A geared transmission can also be used to achieve a desired force exerted by the threaded clamping arm18on the substantially cylindrical element. According to various embodiments of the present invention, the geared transmission is used to convert an input force into a smaller output force. In such embodiments, the geared transmission can increase the number revolutions of the threaded clamping arm18for a given number of revolutions of the pulley26.

The geared transmission can be a planetary geared transmission, epicyclic geared transmission or Ravigneaux geared transmission, or any other suitable type of geared transmission. The transmission compensates for the pitch of the threaded clamping arm18. For instance, if threaded clamping arm18has a given pitch of P (P being a variable equivalent to the number of threads per unit of arm length), more vertical displacement of the retaining member20(represented by the variable V) might be needed than is available, based on the dimensions of the apparatus, in order to obtain the necessary radial displacement (represented by the variable R) of the threaded clamping arm18to engage with the substantially cylindrical element1.An equation relating the pulley circumference (C), the pitch (P), and vertical displacement (V) to radial displacement (R) is shown in Equation 1:
(G)/(C*P)=(R/V)  Equation 1:Where: C=2*π*rπ (pi) is about equal to 3.141590r is the radius of the pulleyG is the gear ratio of the geared transmission

Equation 1 shows that the radial displacement (R) of the threaded clamping arm is a function of the vertical displacement (V) of the retaining member, pulley radius (r), thread pitch (P) and gear ratio (G). Without a geared transmission, the necessary vertical displacement (V) to achieve a desired radial displacement (R) could, in some instances, be too large for the dimensions of the self-adjusting apparatus. Changing the gear ratio (G), using the geared transmission described above, changes the amount of vertical displacement (V) necessary to achieve a desired radial displacement (R). From Equation 1, it is apparent that increasing the output/input ratio (G) of the geared transmission results in less vertical displacement (V) needed to effect the same radial displacement (R). Further, changing the gear ratio can change the magnitude of force imparted by the clamping mechanism. Increasing the output/input ratio (G) of the geared transmission results in less force on the substantially cylindrical element for a given weight on the retaining member.

FIG. 5depicts one embodiment of the clamping mechanism12in assembled form. The threaded clamping arm18is illustrated to have an indexing groove54and clamping arm stopper56. The threaded clamping arm18passes through the ring gear32, cap58and pulley26. An indexing pin60is attached to the cap58. The threaded clamping arm18can be prevented from spinning because it is retained by the indexing pin60built into the cap58. The indexing pin60fits in the indexing groove54machined in the threaded clamping arm18and constrains the threaded clamping arm18to move along its axis, forward or backward. The clamping arm stopper56prevents the threaded clamping arm18from being removed from the ring gear32, cap58and pulley26.

FIGS. 6 and 7illustrate exploded views of the clamping mechanism, from two different perspectives. The geared transmission of the first embodiment is depicted inFIGS. 6 and 7, and comprises an assembly of, at least, one sun gear62, one planet gear64, supported by a planet carrier66, and a ring gear or annulus gear32, shown inFIG. 2. For one set of sun/planet/carrier/ring gears (referred to collectively as a stage), a certain gear ratio is achievable. Since the threaded clamping arm18passes through the center of the transmission, the diameter of the sun gear62is constrained, limiting the gear ratio range available with one stage. Additional stages can be provided in order to achieve a desired gear ratio. Modifying the gear ratio changes the overall transmission ratio, which is the ratio between the vertical displacement (V) of the retaining member20and the radial displacement (R) of the threaded clamping arm18. In various embodiments, it is desirable to have a gear ratio that results in a transmission ratio of R/V between about 0.8 and about 1.2.

The gears of additional stages are illustrated inFIGS. 6 and 7. Sun gears68and70, planet gears72and74and planet carriers62and66are shown. In a presently preferred embodiment, the first stage sun gear and the second stage planet carrier constitute only one part62, i.e. are integral with one another. Likewise, the second stage sun gear and the third stage planet carrier66are integral with each other. The sun gears62,66and70, planet gears64,72and74, and planet carriers62and66are placed inside the ring gear32and engage with a threaded cylinder76, through which the threaded clamping arm18runs.

The sun gear62is the central gear of the system, while the planet gear64is a gear revolving around the sun gear62. The planet carrier66carries one or more planet gears, such as planet gears64,72and74. The ring gear32is the outer gear with teeth facing inward, facing its revolving axis and meshing with the gear teeth of the planet(s).

In the operation of the first embodiment, at least one threaded clamping arm18is displaced by at least one clamping mechanism12, which preferably comprises a geared transmission, activated by the weight of the substantially cylindrical element1on the retaining member20. The clamping mechanism12activates and clamps the threaded clamping arm18to engage the clamping arm18with the substantially cylindrical element1. The clamping cable22transmits the force generated by the weight of the substantially cylindrical element1to the threaded clamping arm18by way of the pulley26. The pulley26converts the vertical movement of the retaining member20into rotational movement of the geared transmission, whose rotational output is the inner-threaded cylinder76. The threaded cylinder76turns, activating the threaded clamping arm18. Therefore, when the pulley26is activated by the displacement of the retaining member20towards the surface of reference, the threaded clamping arm18is displaced radially inward until it engages the substantially cylindrical element1placed within the self-adjusting apparatus10.

The clamping mechanism described in the operation of the first embodiment exerts a clamping force based on the weight of the substantially cylindrical element on the retaining member. The downward force on the retaining member is transmitted by the cable and pulley through the clamping arm back to the substantially cylindrical element. The clamping force on the substantially cylindrical element is proportional to the weight of the substantially cylindrical element and, since the displacement of the clamping arm is in an essentially radial direction, the clamping force is directly proportional to the substantially cylindrical element's weight. In various embodiments, the clamping force is less than or equal to the force due to the weight of the substantially cylindrical element on the retaining member. The clamping force can be between about 0.002 and about 0.6 times the weight of the substantially cylindrical element on the retaining member.

In some embodiments, the clamping arm can exert a substantially constant clamping force regardless of the apparatus's clamping position. In such embodiments, for a given weight, the diameter of the substantially cylindrical element (and, hence, the position of the clamping arm when it engages with the substantially cylindrical element) does not affect the magnitude of the clamping force exerted by the clamping arm.

In the first embodiment, the self-adjusting mechanism is prevented from unclamping the substantially cylindrical element1when weight is placed on the retaining member20. Once the threaded clamping arm18engages the substantially cylindrical element1, the weight of the substantially cylindrical element1on the retaining member20prevents the threaded clamping arm18from disengaging the substantially cylindrical element1. The more weight placed on the retaining member20by the substantially cylindrical element1, the more forcibly the clamping arms18engage the substantially cylindrical element1. In cases where the substantially cylindrical element is subjected to an externally applied horizontal force, the friction between the threaded clamping arm18and inner-threaded cylinder76prevents the threaded clamping arm18from moving radially. In these instances, since the threaded clamping arm18does not move, the tension in the cable22does not change and the retaining member20also does not move. Unlocking the presently preferred embodiment requires lifting the substantially cylindrical element1away from the surface of reference, thereby removing its weight from the retaining member20.

FIG. 8illustrates a self-adjusting apparatus78and clamping mechanism80according to a second embodiment of the present invention. The clamping mechanism80is located at the upper ends of posts82that are attached to and extend upwardly from a base84. The posts82define a receiving area for receiving a substantially cylindrical element placed between them. The receiving area defines an opening between the upper ends of the posts. The clamping mechanism80comprises an unthreaded clamping arm86that exerts a radial force inward on the substantially cylindrical element1(shown inFIG. 15). The radial force applied by the unthreaded clamping arm86is activated by the weight of the substantially cylindrical element1on the retaining member20. The posts82, the clamping mechanisms80, and the receiving area inFIG. 8can have varying features as described in relation to the posts14, the clamping mechanism12and receiving area inFIG. 1.

The second embodiment of the present invention is further depicted inFIG. 9which illustrates the self-adjusting apparatus78as having a shell86, a leg90, a foot92, and a liquid management system, which is substantially similar to the liquid management system of the first embodiment and further comprises a funnel holder94, by means of which the funnel42is engaged with the self-adjusting apparatus. The funnel holder94can be built into one of the legs36(or90) or feet38(or92), or can stand alone. In the second embodiment, the base84, leg90and foot92are substantially similar to their respective counterparts in the first embodiment.

FIGS. 10 and 11illustrate the second embodiment in cross section, showing various preferred components. The clamping mechanism80is depicted as having an unthreaded clamping arm86, a return spring96, the clamping cable22with cable ends28and a fixed pulley98. These are located at the upper ends of the posts82that are attached to and extend upwardly from the base84. The clamping mechanism80is movably engaged by the post82and an unthreaded clamping arm guide100. The clamping mechanism80displaces the unthreaded clamping arm86until it engages with the substantially cylindrical element1.FIG. 11further depicts aspects of the liquid management system which can include the reservoir40, a capillary mat and wick combination48, a capillary mat spring50, and a 90° hose plug52. The liquid management system of the second embodiment can be substantially similar to the liquid management system of the first embodiment. In this illustration, the capillary mat and wick combination48is placed on top of the capillary mat spring50and hangs down into the reservoir in order to contact liquid therein.

FIGS. 12 and 13illustrate an exploded view of the self-adjusting apparatus of the second embodiment78. In addition to the components listed above,FIGS. 12 and 13depict a self-centering mechanism including a flexure spring102and gliders104.

As in the description of the first embodiment, in operation, the unthreaded clamping arm86of the second embodiment is activated by the displacement of the retaining member20. Such displacement is generated by the weight of the substantially cylindrical element1when it is placed on the retaining member20. The clamping cable22transmits the force of the substantially cylindrical element1, deposited on the retaining member20, to the unthreaded clamping arm86. The clamping cable22and the fixed pulley96convert the vertical movement of the retaining member20into radial movement of the unthreaded clamping arm86radially inward. The clamping cable22can be engaged with the retaining member by one of its cable end fittings28engaged with the side of the retaining member20. The other cable fitting28can be lodged in the unthreaded clamping arm86. When the retaining member20is displaced by the weight of the substantially cylindrical element1, the unthreaded clamping arm86is displaced radially inward until it engages the substantially cylindrical element1that has been vertically placed within the opening defined by the posts82.

A return spring96can be used to automatically return the apparatus to its starting position, or rest position, when weight is removed from the retaining member20. The return spring96pulls the unthreaded clamping arm86radially outward while bringing the retaining member20to its highest position. The return spring96is preferably placed inside the unthreaded clamping arm86to prevent rust and save space inside the reservoir40. The maximum ending position and clamping position of the second embodiment are defined in a similar manner as they are above for the first embodiment.

The clamping mechanism80is located at the upper end of the post82in the second embodiment and can be secured in place by the unthreaded clamping arm guide100. Alternatively, the clamping mechanism can be placed elsewhere on the post. The fixed pulley98of the second embodiment does not turn. The clamping cable22slides circumferentially around the pulley98when the retaining member20is displaced. The friction generated between the clamping cable22and the fixed pulley98varies according to the tension on the clamping cable22.

The clamping cable22circumscribes the pulley at least once, corresponding to a total winding angle of θt. The substantially cylindrical element1, sitting on the retaining member20, applies tension to the clamping cable22, pulling the unthreaded clamping arm86radially inward. As long as the retaining member20is moving and the unthreaded clamping arm86is not engaged with the substantially cylindrical element1, the friction generated between the fixed pulley98and the clamping cable22is low enough that the mechanism remains moveable. When the unthreaded clamping arm86makes contact with the substantially cylindrical element, the tension in the clamping cable22increases. In this situation, the proper θtwill deliver enough friction between the clamping cable22and the fixed pulley98to lock the mechanism. In this manner, the substantially cylindrical element is prevented from unclamping the substantially cylindrical element due to its weight on the retaining member20, preventing it from moving relative to the self-adjusting apparatus. The effectiveness of this mechanism depends on θtand on the coefficient of friction (μ) between the fixed pulley98and the clamping cable22, according to Equation 2, which is an equation relating the equilibrium tensions between two portions of a cable wound around a pulley:

ⅇ-μ⁢⁢θt=T1T2=DEquation⁢⁢2
Where:e is a constant about equal to 2.71808183,μ is the coefficient of friction,θtis the total cable winding angle,T1is the tension in the portion of the cable22between the unthreaded clamping arm86and the fixed pulley98,T2is the tension in the portion of the cable22between the fixed pulley98and the retaining member20, andD is the ratio between T1and T2.

In order to illustrate the meaning of this equation by numerical example, exemplary values are used for the different parameters. Hence, assuming a coefficient of friction (μ) of 0.3, a total cable winding angle θtof 2 turns (12.5462 radians), and there are no external perturbing forces acting on the substantially cylindrical element, the equation returns:

This indicates that, with the parameter values used here, the tension between the unthreaded clamping arm86and the fixed pulley98is 0.023 times the tension between the fixed pulley98and the retaining member20when the substantially cylindrical element is not subjected to any external perturbation. Since the tension T2is proportional to the weight of the substantially cylindrical element, the force applied by the unthreaded clamping arm86on the substantially cylindrical element is substantially smaller than the force exerted by the substantially cylindrical element1on the retaining member20. This allows the unthreaded clamping arm86to engage the substantially cylindrical element1without damaging the element. Exemplary values of μ and θtresult in values of D between about 0.08 and about 0.00008 for various embodiments of the present invention.

In cases where the substantially cylindrical element is subjected to an externally applied horizontal force, the unthreaded clamping arm86will resist moving radially outward. This is due to the frictional force between the cable22and fixed pulley98. Because the coefficient of friction (μ) and the total cable winding angle (θt) remain the same, increasing the tension T1by exerting an external force on the clamping arm86does not result in changes in T2until the friction between the cable22and fixed pulley98is overcome, that is to say, until the force on the unthreaded clamping arm86is 1/D times the weight of the element. Unlocking the presently preferred embodiment requires lifting the substantially cylindrical element1away from the surface of reference, thereby removing its weight from the retaining member20. In cases where the externally applied horizontal force is sufficient to overcome the frictional force between the cable22and fixed pulley98, once the externally applied force is removed, the clamping mechanisms80will clamp the substantially cylindrical element and return the element to a substantially vertical position.

Both embodiments above describe a retaining member20. One embodiment of the retaining member20is illustrated inFIG. 14. Similar toFIGS. 4 and 10, the retaining member20ofFIG. 14can be located inside the reservoir40and is preferably designed to be always concentric with the posts14or82. In an embodiment, this concentric positioning is provided by the gliders104which interact with the posts14or82. The gliders104allow the retaining member20only substantially vertical motion. At least two posts14or82and their corresponding grooves are preferably provided, which assures that the retaining member20is always substantially perpendicular to the posts14or82. Although depicted as an inflexible mesh, in another embodiment, the retaining member can be provided as rigid body, such as: a flat tray, a frusto-conical platform, a bowl, etc.

The clamping cable22illustrated inFIG. 14is joined to the retaining member20by a loop, which passes around a small rod106press-fitted in the retaining member20. Alternatively, the clamping cable22can be engaged with the retaining member by means of the cable end fitting28or any other means commonly known in the art. The retaining member20depicted inFIG. 14is shown to have a centering mechanism comprised of flexure springs102and a retaining member center pin108.

The centering mechanism can help move a substantially cylindrical element1into a substantially vertical position. The centering mechanism can automatically center the substantially cylindrical element1just before it touches the retaining member center pin108. To center the substantially cylindrical element1before it touches the retaining member center pin108, a concentric spring action can be used to engage substantially cylindrical element1.

The concentric spring action is provided by a flexure spring mechanism. In one embodiment, the flexure spring mechanism can have at least two flexure springs102. The flexure springs102are preferably shaped to make contact with the substantially cylindrical element1and center it before it touches the retaining member center pin108. Moreover, the shape of the flexure spring102is preferably designed such that the flexure spring102can have an increasing degree of stiffness the greater the diameter of the element being centered. This can make the flexure springs102deliver more centering force as the substantially cylindrical element's diameter increases. This can be desirable when centering large and heavy elements. In another embodiment, a single flexure spring has a single ring-type member that acts on the perimeter of the substantially cylindrical element. The substantially cylindrical element can be centered as it is lowered on to the retaining member20, and engages with the retaining member center pin108, the highest point of the retaining member.

The retaining member center pin108can prevent the substantially cylindrical element1from sliding on the surface of the retaining member20, as illustrated inFIG. 15where a tree is illustrated as being clamped in the self-adjusting apparatus10of the first embodiment. The self-adjusting apparatus78of the second embodiment can function in a similar manner when the retaining member20is the same in both embodiments. The retaining member center pin108securely retains the substantially cylindrical element1. The retaining member center pin108can take the shape of a nail, a conical shape or any shape that has a narrow end, which could contact the base portion of the substantially cylindrical element1. A parabolic or conically shaped center pin108can fit a hole of many different diameters preformed in the substantially cylindrical element. The embodiments described above can have one or more retaining member center pin(s)108.

Rigid conical retaining members ensure that the substantially cylindrical element is centered at all times, even when not desired. The retaining member center pin108can also retain, in an off-center position, a substantially cylindrical element that would have been purposely pushed off-center by the user, against the flexure spring102. Flexibility of the flexure spring102can, therefore, be desirable. Flexibility can be desirable when off-centering the substantially cylindrical element, such as in order to compensate for the curve or angular variation of a substantially cylindrical element that was crooked or curvy. This could be accomplished by off-centering the contact point between the substantially cylindrical element and the retaining member center pin108, with the aim of clamping the substantially cylindrical element in a more generally vertical position.

The portion of the capillary mat44or capillary mat and wick combination48, described previously, to contact the base of the substantially cylindrical element is preferably positioned so that it is at least as high as the retaining member center pin108. The substantially cylindrical element's bottom can make contact with the capillary mat44or capillary mat and wick combination48. The capillary mat44or capillary mat and wick combination48can be elevated to the desired height by the capillary mat spring50. The capillary mat44or capillary mat and wick combination48are preferably somewhat cushioned.

Although the presently described embodiments refer to cable and pulley systems to link the retaining member20with the clamping mechanisms12and80, other embodiments can have the retaining member activate the clamping mechanism through a gear and pinion system or any other system known in the art in which the clamping arms of the clamping mechanism move along a radial axis in order to clamp the substantially cylindrical element.