Patent Publication Number: US-6220631-B1

Title: Stabilizing skeg device

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of applicants&#39; patent application Ser. No. 09/465,923 filed Dec. 17, 1999 for “Stabilizing Skeg Device” now abandoned, which is a continuation of Ser. No. 08/922,855 filed Sep. 3, 1997 now U.S. Pat. No. 6,007,101. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     This invention relates to an improved performance stabilizer for snowboards, skis and other related snow-travel devices, and more particularly, to an adjustable, skegdeployable skeg structure that functions to improve the maneuverability, the tracking and the stability of such devices which travel on and over a snow surface. For the purpose of disclosure herein, a preferred embodiment, and certain modifications, of the present invention are described chiefly in the realm of snowboards with respect to which the invention has been found to offer particular utility. 
     As is pointed out in the companion, underlying patent-application history from which this present application continues, and focussing especially on snowboards, such boards in recent years have become increasingly popular sporting devices. For a large number of reasons, snowboards afford opportunities for movement and maneuverability over a snow surface which offer a variety of interesting dimensions to snow-sporting activities. In the context of such activities, there is a great deal of interest in equipping a board, like a snowboard, with configurations, devices, etc. that can offer a range of subtle, sophisticated, and dramatic maneuvering and control capabilities. Especially, there is a strong interest in having the versatility of adaptability in the performance of snowboards to meet numerous, different snow conditions. 
     The stabilizer/skeg structure of the present invention addresses several of these interests and desirabilities in ways which offer a very high degree (and range) of maneuverability, control and adjustability. It does so in a relatively simple structural arrangement which can either be employed as an “add-on” system for an otherwise conventional snowboard (or other snow devices), or as a system initially integrated (as wholly as possible) into the body of a snowboard. 
     According to the invention, proposed thereby, in several modifications, is a skeg structure that is adapted for mounting either as an individual, or as part of a plurality of like structures, on and with respect to the body of a snowboard, or a like device. This skeg structure, in one of its preferred add-on forms, includes (a) a base (also referred to as an anchor structure) that is readily securable to a board at different selected locations, (b) a skeg blade which is deployable (either through a slot-like opening in the body of a board, or as an outrigger structure) to offer different levels of downward projection (for snow-surface penetration and engagement) from the undersurface (also referred to as the underside, snow-contacting surface) of a board, and (c) an appropriate mounting structure which mounts the blade on the base in such a manner as to accommodate adjustable, and relatively widely variable, blade deployment in the manner just suggested. The blade motion which is accommodated by this mounting structure is also referred to herein as adjustable, travel-limited, yieldable, spring-biased motion. The proposed skeg structure is one wherein the skeg blade normally operates with quickly responsive, vertically moveable (rotational and/or linear translational) reaction to an underlying snow surface, and against the action (variable, if desired) of a suitable biasing spring. Such a spring allows the blade to shift with yielding reaction in order to accommodate changing, underlying snow conditions as a board travels over snow. Additionally, and according to the invention, the user is afforded an ample opportunity to control the nominal degree of initial, non-reactive deployment which a blade exhibits in the absence of contact with snow. 
     Among the preferred embodiments of the invention that are illustrated and described herein, certain ones employ, in the mounting structure for a blade, a rotatable shaft having a polygonal, cross-sectional, skeg-blade-receiving end that fits within a generally matching, polygonal receiving socket in the blade. This shaft and socket arrangement supports the blade in a locked, positive-drive manner, permitting rotary blade deployment, and appropriate, responsive yield reaction, with the blade and shaft operating under all circumstances as a substantially fixed-configuration unit. With this positive-drive feature of the invention present, there is essentially no opportunity for the blade to become loosened from the shaft in any manner that would permit it to rotate relative to the shaft. Such a “locked” arrangement is advantageous in certain kinds of snowboarding conditions. 
     Another feature offered by the present invention involves a blade construction per se which is generally thin and planar, but which is characterized by a very gentle taper progressing outwardly into the expanse of the blade away from the point at which the blade is mounted (through the rotatable shaft in the mounting structure) on the base. This tapered arrangement may either be a simple taper that is defined by the convergence of two planes slightly angled relative to one another, or, in the context of a further modification, by a plurality of converging planes, such as three or more planes, which define a blade characterized with a stepped, or differential, bevel configuration. 
     Such a beveled construction enhances what might be thought of as the knife-like performance of the blade as such engages underlying snow. This kind of construction is considered to offer interesting performance advantages under certain kinds of snow conditions. 
     Yet another modification proposed by the present invention includes a deployment biasing and adjustment structure, or mechanism, which sets the nominal degree of downward projection, i.e., projection from the undersurface of a snowboard, utilizing a relatively moveable cam and follower structure. Such a structure offers a very high degree of fine control over deployment, and is one which is relatively simple in construction. Within such a cam and follower arrangement, there is disclosed herein an embodiment wherein the cam structure takes the form of a rotary cam element, which element is mounted on the base in the skeg structure, and includes a sloped cam surface. Spring-biased detent structure is interposed the cam element and the base so as to permit releasable detent latching, or catching, of the element in different, rotated, angular positions. The follower in the cam and follower structure takes the form, as disclosed herein, of a unit anchored for rotation with a shaft that mounts a blade for rotational deployment. This follower has a projecting finger (also called a finger-like projection) that rides on the cam surface in the cam element. The upper surface of the cam element may, if desired, be furnished with follower-receiving, preselected registry indentations or depressions which may be disposed angularly on the cam surface in a relationship that ties in with the location of components in the detent structure just mentioned. 
     Still another important embodiment of the invention proposes a skeg structure including a unitary, combined skeg blade and mounting structure, wherein a skeg blade is formed as a portion of an elongate, springy, reed-like device (also called herein a common spring-reed component). A slider is employed to adjust the projection deployment of the blade, with such adjustment relating to the slider&#39;s position along the length of the “reed portion” of the device. The slider acts in a wedged condition between this reed portion and the mounting base in the skeg structure. Spring force exerted by bending in the reed portion can be adjusted as well, and via another slider which can be selectively positioned to define a nip region bracketing the reed portion effectively between this second-mentioned slider and the mounting base. 
     In various embodiments of the invention, the spring force which acts yieldably to permit blade movement necessitated by travel over and in a snow surface is adjustable. 
     Still a further important embodiment of the skeg structure of the present invention features a deployable skeg blade which can move in a defined, linear, plunger-like manner. 
    
    
     Various other features and advantages that are offered and attained by the present invention will become more fully apparent as the description which now follows is read in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary, rear-end perspective view of a snowboard equipped with plural skeg structures constructed in accordance with one preferred embodiment of the present invention. Specifically, this board is shown to be equipped with one pair of rearend-disposed, laterally outwardly positioned skeg structures having blades that operate through slots provided on opposite sides of the board. Blades in these two skeg structures are movably (rotationally) deployable through these slots. 
     FIG. 2 is an isolated and exploded perspective view of the particular skeg structure that is pointed to by serpentine arrow  2  in FIG.  1 . This view, which is taken generally in the direction indicated by arrow  2 , is on a scale which is larger than that employed in FIG.  1 . 
     FIG. 3 is an exploded view taken generally along the line  3 — 3  in FIG. 2, illustrating several isolated components that are present in the skeg structure of FIG.  2 . 
     FIG. 4 in an elevation taken generally along the line  4 — 4  in FIG.  3 . 
     FIG. 5 is a simplified, fragmentary view on a slightly smaller scale than that employed in FIGS. 2-4, taken generally along the line  5 ,  6 — 5 ,  6  in FIG. 1, showing generally a modified skeg structure which includes an outrigger-type skeg blade in a condition of full deployment. 
     FIG. 6 is a view, on about the same scale as that used in FIGS. 2-4, also taken generally along line  5 , 6 — 5 , 6  in FIG. 1, showing another modified form of skeg structure. 
     FIGS. 7,  8 A and  8 B are views, each on a scale which is slightly larger than that present in FIG. 6, illustrating, in an isolated fashion, two modified forms of a rotary, deployable skeg blade constructed in accordance with the invention. FIGS. 7 and 8A are to be viewed and read together as an illustration of one of these two modified blades, and FIGS. 7 and 8B together as an illustration of the other modified blade. Each of these two modified forms of blades is characterized as having a stepped, differential-bevel configuration. FIGS. 8A,  8 B are partial sectional views taken generally along the line  8 A,  8 B- 8 A,  8 B in FIG.  7 . 
     FIG. 9 is a view similar to that presented in FIG. 5, on a different scale, and showing (in simplified form) a modified skeg structure which includes many components carried, effectively, within the body of a snowboard. 
     FIG. 10 is a perspective view like that pictured in FIG. 1, drawn on a scale which is substantially the same as the one chosen for FIG. 1, and illustrating skeg structures (four) constructed in accordance with the present invention as employed with skis. 
     FIG. 11 is a fragmentary plan view, drawn on a larger scale than that used in any of the other drawing figures mentioned so far, illustrating a modified form of skeg structure, wherein a rotary, deployable and moveable skeg blade has its nominal deployment condition controlled by cam and follower structure constructed in accordance with the present invention. 
     FIG. 12 is a fragmentary cross-sectional view taken generally along the line  12 — 12  in FIG.  11 . 
     FIG. 13 is a simplified, smaller-scale, side view of the skeg structure shown in FIGS. 11 and 12, generally illustrating three, different, pre-defined, “nominal” deployments offered by this skeg structure. 
     FIGS. 14-16, inclusive, present, each on a scale similar to that used in FIG. 11, three different views of another modified form (i.e., a “plunger” form) of the invented skeg structure. 
     FIGS. 17-20, inclusive, show yet a further modified form (i.e., a reed-like form) of the skeg structure of the present invention. These four figures are drawn with roughly the same scale chosen for FIG.  11 . 
     FIGS. 21-24, inclusive, illustrate different views of still another modified form of the invention—this one featuring a skeg blade which forms part of a springy, reed-like structure, and wherein deployment, and deployment biasing-spring force, are independently adjustable through the use of two positionally adjustable sliders. These four figures are prepared in approximately the same drawing scale used in FIGS.  17 - 20 . 
    
    
     DETAILED DESCRIPTION OF, AND BEST MODE FOR CARRYING OUT, THE INVENTION 
     Turning now to the drawings, and referring first of all to FIGS. 1-4, inclusive, indicated generally at  30  in FIG. 1 is the rear end portion of an otherwise conventional snowboard. Mounted on this end of board  30  are two skeg structures  32 ,  34  which are constructed in accordance with a preferred embodiment of the present invention. As will be more fully explained. These two skeg structures, which are effectively mirror-image structures, are mounted as by screws on the upper surface of the board, immediately adjacent two, elongate (longitudinally extending) through-body slots  30   a ,  30   b  which are associated, respectively, with structures  32 ,  34 . It is through these two slots that the skeg blades contained in structures  32 ,  34  are deployed. Structures  32 ,  34  take the form of what are also referred to herein as add-on type structures, in the sense that they can be acquired separately and mounted later, in relation to the date of board construction. 
     FIGS. 2-4, inclusive, illustrate details of the construction of the skeg structure  32 . As was previously mentioned, structures  32 ,  34  herein are mirror-image structures, but in all other respects are substantially identical. Accordingly, the description which now follows that relates to skeg structure  32  can be viewed as being also a full constructional and operational description of skeg structure  34 . 
     Thus, included within skeg structure  32  are an anchor structure  36 , a skeg blade  38  and mounting structure (also referred to herein as deployment biasing and adjustment structure)  40  which is operatively interposed blade  38  and anchor structure  36 . 
     Mounting structure  36  includes a mounting base plate  36   a  having an upwardly projecting boss  36   b  which plays a role in deployment adjustment, and two screw-accommodating board-mounting apertures  36   c . It is via apertures  36   c  that screws (not shown) are employed to anchor structure  32  onto a board, such as snowboard  30 . 
     Rotatably received within a pair of spaced journal structures  36   d ,  36   e  which form part of base plate  36   a  is an elongate, rotatable shaft  42  having a skeg-blade-receiving end  42   a  which projects generally toward the viewer in FIG.  2 . End  42   a  is formed with a polygonal perimetral structure, as such structure is viewed effectively along the long axis  42   b  of shaft  42 , which perimetral structure is generally square in shape. Shaft  42  is also referred to herein as a loadable/unloadable biasing element. 
     Suitably anchored to shaft  42  in the region therealong which extends between journal structures  36   d ,  36   e  is a laterally projecting arm structure  44 . The outer portion of this arm structure includes, in a projection  44   a , an internally threaded through-bore which threadably receives a deployment adjustment screw (also called an adjustment structure)  46  whose lower end in FIG. 2 nominally engages the upper surface of previously-mentioned boss  36   b . Operatively, interposed arm  44  and base plate  36   a  is a coiled biasing spring  48 . This spring, which resides in a loaded (non-relaxed) condition in the skeg structure, rotationally urges arm  44  for clockwise rotation along with shaft  42   a  about axis  42   b . The limit position for such rotational bias in skeg structure  32  is defined by the particular adjusted (threaded) condition of adjustment screw  46  within projection  44   a . Recalling that, as was mentioned earlier, the lower end of screw  46  nominally tends to rest upon, and in force-biased contact with, the upper surface of boss  36   b , it will become apparently shortly that manipulation of screw  46  establishes the nominal deployment condition for blade  38 . This condition is referred to herein as a yieldably biased deployment condition. In the absence of any external force tending to disrupt such a nominal “rest” condition, the components in the mounting structure in skeg structure  32  remain positioned in the manner defined by the condition of screw  46  relative to projection  44   a.    
     According to one of the special features of the present invention, and in relation to the squared end  42   a  (also called herein a positive drive structure) in shaft  42 , blade  38  is locked into a positive-drive relationship with shaft  42 , in which condition acts as a single unit with the shaft. Blade  38 , which has the perimetral configuration generally illustrated in FIGS. 2 and 4, includes a mounting region  38   a  which is furnished with an elongate through-passage  38   b . The near end  38   c  of passage  38   b  in FIGS. 2 and 4, which end appears in FIG. 3 as the left side of blade  38 , is generally conically shaped This end communicates with a squared, rectangular (polygonal) passage socket  38   d  that lies at the opposite end of the passage. The perimetral outline of socket  38   d  substantially matches (in a clearance-fit manner) the outer configuration of shaft end  42   a , whereby, with this shaft end inserted into socket  38   d  (the mounted condition for blade  38  in structure  32 ), the blade and the shaft are positively, drivingly locked to one another against any possibility of relative rotation about the long axis of arm  42 . A screw  50  shown in FIGS. 2 and 3 functions to anchor blade  38  into such a condition on end  42   a  in shaft  42 . 
     This positive-drive interconnection which is thus provided for blade  38  relative to shaft  42  in the skeg structure now being described, is a feature which securely anchors the blade on the shaft against relative rotation. Importantly, it thus guards against unwanted angular “slippage” during use with a snowboard. While, in the particular structure now being described, a square, perimetral outline is defined and illustrated for shaft end  42   a  and for socket  38   d , it should be understood that other faceted, polygonal shapes could be chosen, each one of which would furnish essentially the same kind of positive drive connection between the blade and the shaft. 
     During operation, preselected, nominal blade deployment through the associated slot in board  30  (slot  30   a ) is implemented through operation of screw  46 . Biasing spring  48 , under nominal conditions, i.e., under conditions where substantially no external force is applied to blade  38 , keeps the blade and shaft in a releasably stale and appropriate fixed positions. When blade  38  engages a snow surface on the underside of board  30 , it is permitted, as needed, to yield and to swing upwardly through slot  30   a  against the biasing action of spring  48 . This blade motion for blade  38  is referred to herein as arcuate, pivotal motion of the blade relative to base  36 . The term “arcuate” is used herein to describe motion which is generally curvilinear. The term “pivotal” is employed to describe a special case of arcuate motion—namely one which occurs with respect to a pivot axis or the like. As illustrations of the intended meanings of these two terms, the motion generally of the end of an elongate element as such is bent along its long axis is arcuate motion which is not necessarily pivotal motion. The swinging of, for example, of a door on hinges is arcuate motion which is also pivotal motion. 
     Blade  38  will not slip in relation to its angular condition on shaft  42 . When the particular external-force condition that produces such a yieldable deflection in blade  38  goes away, spring  48  reliably returns the blade exactly to the user-prechosen, nominal deployment for blade  38 —such being defined by engagement of the bottom end of screw  46  on the upper surface of boss  36   b . No amount of normal blade deflection (as a consequence of engagement with different kinds of underlying snow surfaces) will ever cause the blade to become unlocked from the angular position initially chosen for it on shaft  42 . 
     Addressing attention now to FIG. 5, here there is shown generally, and in a very simplified form at  52 , a modified form of pivotal-blade skeg structure mounted on the rear end of board  30 . Structure  52  includes a deployable, spring-biased and reactable skeg blade  52   a  which, instead of extending downwardly through an accommodating through-body slot in the board, resides as an outrigger structure on that side of board  30  which is facing the viewer in FIG.  5 . In all other respects, the other structure present in skeg structure  52  is like that which has just been described for skeg structure  32 . 
     FIG. 6 illustrates another modified form of pivotal-blade skeg structure designated at  54 . In many ways, skeg structure  54  is like skeg structure  32 . Here, however, an elongate deployment adjustment screw  56 , which is the counterpart of previously-mentioned adjustment screw  46 , has its lower end acting on a specially shaped boss structure  58  which has, on its upper surface, the curvature clearly pictured in FIG.  6 . With this structural arrangement, one can see that the bottom end of screw  56  substantially always engages (when it does so engage) the curved surface of boss  58 , so as to have the long axis  56   a  of the threaded portion of screw  56  substantially normal to a tangent to the curvature of boss  56  at the point of contact. Such an arrangement provides a very sure footing for engagement between screw  56  and boss  58 . 
     Skeg structure  54  also includes another modification which takes the form of a biasing-force screw-adjustment structure  60 , including an adjustment screw  60   a  which is threadably received in a suitable threaded through-bore in a collar  60   b . Collar  60   b  is appropriately anchored to one of the ends of a coiled biasing spring  62  that is the counterpart of previously-mentioned biasing spring  48 . The lower end of screw  60   a  engages the upper surface of the mounting base provided in skeg structure  54 . And rotational adjustment of this screw (at the selection of the user) is effective to change the biasing force applied by spring  62  ultimately to the deployable skeg blade  54   a  provided in skeg structure  54 . 
     Turning attention now to FIGS. 7,  8 A and  8 B, here, depending upon the specific chosen one of two ways of reading these views together, there are illustrated two modified forms of pivotal skeg blades constructed in accordance with the present invention—each possessing a tapered, broad-area, somewhat planar expanse. This expanse is also referred to herein as a stepped, differential-bevel configuration which is defined by plural, slightly angularly infused, converging planes present on one side (the near side in FIG. 7) of the blade. FIGS. 7 and 8A should be read together (with regard to the solid lines pictured in those two figures) as an illustration of a single-stepped (two-plane) configuration. FIGS. 7 and 8B should be read together (with attention in FIG. 7 focused both on the solid lines used therein and on the dashed-double-dot line therein) as an illustration of a duel-stepped (three-plane) configuration. 
     Thus, and directing attention initially toward FIGS. 7,  8 A together, here there is shown a modified pivotal skeg blade  64  having, as can be seen with FIGS. 7 and 8A read together, a single-stepped, two-plane, tapered configuration, wherein the side of the blade that faces the viewer in FIG. 7 (the side which appears at the right side of FIG. 8) being defined by the two planes designated  64   a ,  64   b . Planes  64   a ,  64   b  intersect at a shallow angle along the solid line shown at  64   c  in FIG.  7 . 
     FIGS. 7 and 8B, as read together, illustrate a blade  64  having that same side of the blade just specifically referred to (i.e., the side facing the viewer in FIG. 7) defined by three planes of intersection, including previously-mentioned planes  64   a ,  64   b , and a new plane pictured at  64   d . Planes  64   a ,  64   d  intersect along the line shown as a dash-double-dot line presented at  64 e in FIG.  7 . 
     A blade constructed in accordance with either one of these two modifications presents to a snow surface an edge which is more knife-like than that which is presented by the previously-described skeg blades. Such a differential, tapered configuration offers advantages in certain kinds of snow/ice conditions, wherein the presence of blade “knife” action is important to assuring proper penetration of the underlying snow surface. 
     With attention now directed to FIG. 9, here there is shown, generally from the same point of view as that taken in FIG. 6, another modified, pivotal-blade  66  form of skeg structure which is constructed in accordance with the present invention. Specifically what is shown here, in a very simplified form, is a non-add-on type of construction according to the invention regarding which construction substantially all of the operational components of the system are contained, so-to-speak, well within, and principally within, a suitable internal area  68  provided within the body of a device, such as snowboard  30 . Appropriate sizes for the various components of any one of the several different skeg-structure modifications that have been described so far herein can be chosen in order to allow such internal placement. And, there are many different ways of accomplishing this, all of which are well within the skills of those skilled in the relevant art. In FIG. 9, structure  66  is shown including a somewhat narrow-profile skeg blade  66   a . Blade  66   a  deploys rotationally (pivotally) about and with respect to an axis shown at  66   b . Skeg structure  66  is further illustrated as including a low profile cover  66   c  which is suitably secured to board  30  overhead the other components in structure  66  in board  30 . 
     As was mentioned earlier, the skeg structure of the present invention is suitable for use with a variety of snow traveling devices. Specifically pictured in FIG. 10 is a rendition of this invention as units incorporated with the rear ends of otherwise conventional skis, shown generally at  70 . Each of the two skis presented in FIG. 10 is furnished with a pair of skeg structures, each of which is very much like previously described skeg structure  32 . In the ski arrangement pictured, rotationally deployable skeg blades are received and movable within and through body slots provided on opposite lateral sides of the skis, the two skeg structures provided for each ski are slightly longitudinally offset on the bodies of the skis. 
     Pictured in FIGS. 11-13, inclusive, is yet another modified form of a pivotal-blade skeg structure constructed in accordance with the present invention. Specifically, these three figures illustrate a structure which features a cam and follower type mechanism for adjusting, selectively, different, nominal skeg-blade deployments relative to a snowboard. In these figures, the snowboard pictured continues to be represented and referred to with reference numeral  30 . 
     Thus, shown generally at  72  in these three figures is a cam and follower skeg structure mounted on board  30  (the rear end of the board) as an add-on to the board. Structure  72  is anchored to the board through a mounting base  74  which, with the exception of certain changes that will be discussed shortly, is the equivalent of the mounting base structure described earlier for skeg structure  32 . Shown at  76  is an angularly, rotatably, pivotally deployable skeg blade  76  which is substantially the same in construction as previously discussed blade  38 . Blade  76  is anchored in the same kind of positive drive manner described earlier to an end of a rotatable shaft  78  which is supported, for rotation about its long axis  78   a , in journals  80 ,  82  that are joined to, and may in fact be an integral part of, base  74 . 
     Anchored to, and for rotation as a unit with, shaft  78  is a radially projecting structure  84 , the outer, finger-like portion in which acts as a cam follower in structure  72 . A suitable configuration for structure  84  is clearly illustrated in FIGS. 11,  12 . Acting as a biasing spring (a rotational biasing spring) in skeg structure  72  is a spring shown at  86 . The opposite ends of this spring include one end which acts on follower  84  and another end acting through biasing-force adjustment screw  88  with the upper surface of mounting base  74 . Screw  88  is the counterpart of screw  60   a  shown in FIG.  6 . It thus performs the function of changing selectively the biasing force which is exerted by spring  86  ultimately on blade  76 . As can be seen, blade  76  is mounted for movement, and is deployed, through a slot  90  provided through the body in board  30 . 
     Coacting with follower  84  to form what is referred to herein as a cam and follower structure, is a rotary cam element  92  which is appropriately mounted on and for rotation about axis  92   a  with respect to base  74  at the location generally shown. Axis  92   a  extends generally at a right angle relative to axis  78   a . The upper cam surface of element  92  is inclined across the upper face of the element, such inclination being clearly pictured in FIG.  12 . This cam surface is provided with three elongate, radially disposed quadrature-located indentations, valleys or depressions, such as the three depressions shown at  92   a ,  92   b ,  92   c . With rotation of cam  92  about its rotational axis  92   a  through manipulation of a finger grippable paddle  92   d  which forms part of the cam element, the undersurface of follower  84 , where such undersurface projects essentially radially over the cam element&#39;s cam surface (relative to axis  92   a ) moves in relation to the position (the rotational position) of that cam surface. The three indentations just mentioned at  92   a ,  92   b ,  92   c  function to receive and stabilize the projecting outer portion of follower  84  in three different conditions which can be thought of herein as being (1) a full deployment condition, (2) a moderate deployment condition, and (3) a nondeployment condition. Deployment is used in this last statement in relation to whether or not the lower part of blade  76  extends downwardly from the undersurface of board  30 . The elements in the cam and follower structure, as such are pictured in FIGS. 11 and 12, are shown in relative conditions wherein blade  76  is fully deployed, and this is the condition specifically visible for blade  76  in FIG.  12 . 
     Referring for a moment to FIG. 13, in this figure, blade  76  is shown in three ways: first, and in solid outline, in its fully deployed condition; second, in dashed lines, in a moderate deployment condition; and third, in dash-dot lines, in a nondeployment condition. 
     In the full-deployment condition, one can see that the lowermost portion of the blade extends downwardly below the undersurface of board  30  by a distance D 3 . 
     With rotation of cam  92  90° in a counterclockwise manner with respect to the point of view taken in FIG. 11, the outer extremity of the cam follower drops into depression  92   b  to define the moderate-deployment condition for blade  76 . Such moderate deployment is shown in FIG. 13 with the blade pictured in dashed outline. With this level of deployment, the underextremity of the blade is spaced below the undersurface of board  30  by a distance D 2 . 
     With another 90° counterclockwise rotation introduced into cam  92 , the outer extremity of the follower drops into depression  92   c , in which condition blade  76  is substantially non-deployed. This condition is shown in FIG. 13 in dash-dot outline. 
     On a final note with respect to skeg structure  72 , furnished in this structure in accordance with the invention, in the interfacial region between the underside of cam  92  and the upper surface of base  74 , there are provided plural, spring-action detent mechanisms, one of which is shown generally in dashed lines at  96  in FIGS. 11 and 12, and each of which conventional in construction. Mechanism  96  includes three, quadrature-displaced detent sockets formed in the upper surface of base  74 , and a single, spring-biased, movable plunger  96   a  (see FIG. 12) carried in, and on the underside of, cam  92 . Such detent mechanism acts to stabilize the rotational position of cam  92  with the cam positioned in each of the three conditions wherein follower  84  engages a depression in the cam surface. 
     FIGS. 14-16, inclusive, illustrates still another modified form of skeg structure constructed in accordance with the present invention. Here, and speaking just generally, what is shown is a plunger-style, linear-translational-motion (non-arcuate-motion, non-pivotal-motion), skeg structure  98  which is mounted as an add-on to board  30  near the board&#39;s rear end. Structure  98  is designed for deployment of a plunger-like skeg blade  99  through an appropriate, accommodating, through-body slot furnished in the board. 
     Structure  98  includes an overhead housing (also called a guide structure)  100  having a base portion  100   a  that is directly anchored to the upper surface of board  30 . Housing  100  is also referred to herein as substructure which defines an environment permitting linear, translational relative motion between blade  99  and board  30 . Screwed downwardly into housing  100  from the top surface thereof are two adjustment screws (spring-action adjustment structure) shown at  102 ,  104 . Stems, such as stem  102   a  in screw  102 , axially freely receive the upper ends of compression biasing springs, such as spring  105  which is associated with screw  102 . The lower ends of these biasing springs acts on the upper portion of blade  99  in structure  98 , which skeg blade acts through slot  106  (generally mentioned just immediately above) provided in board  30 . Lateral blade extensions such as the two shown at  99   a ,  99   b  for blade  99  in FIG. 15, prevent the blade from passing downwardly completely through and escaping slot  106 . 
     A deployment adjustment screw structure  108 , which is formed as an assembly pictured in exploded view in FIG. 16, has a lower-end structure  108   a  which is capturedly received within a suitable receiving space  99   c  in plunger blade  99 . 
     Within skeg structure  98 , the amount of nominal deployment chosen for blade  99  is selected by turning, in one direction or the other, the adjustment screw that forms part of structure  108 . Structure  108  effectively defines the maximum amount of possible deployment for blade  99  under each adjusted condition, and the blade is urged downwardly, to rest nominally in this selected deployment condition, under the influence of the two compression biasing springs. The level of biasing force exerted downwardly on blade  99  can be adjusted through turning of screws  102 ,  104  in one direction or another. 
     When a skeg structure such as structure  98  is put into use, skeg blade deployment chosen by the user is adjusted through manipulation of the parts in deployment adjustment structure  108 , and the biasing force exerted by the springs mentioned is adjusted through manipulation of screws  102 ,  104 . With operation and use of a snowboard employing skeg structures like skeg structure  98 , when it is necessary for the blade to yield against the biasing action of the associated biasing springs, the blade moves upwardly principally translationally into the downwardly facing chamber within housing  100 , against a rising compression in one or both of the biasing springs. An interesting feature of this condition is that yielding movement of blade  99  is both plunger-like (translational) in nature, and in certain instances, rocker-like in character. Such rocker-like behavior is accommodated by the presence of the two, laterally-spaced biasing springs such as spring  104 , and this behavior allows the blade to accommodate snow-surface conditions in a specific way which is different from the types of yielding engagement furnished by the previously-described skeg blades. 
     Turning attention now to FIGS. 17-20, inclusive, here there is shown a very simply constructed, flexible, reed-like, arcuate (but not pivotal) motion, skeg structure which is prepared in accordance with yet another modification of the present invention. In particular, these four figures illustrate a unitary, reed-like skeg structure which includes many fewer components than do the previously described skeg structures. 
     In FIG. 17, this reed-like skeg structure is designated generally at  110 , and looking at FIG. 17 along with the other drawing figures in the collection just mentioned, one can see that this structure  110  is elongate in nature. Structure  110  includes one end  110   a  that forms a “mounting base” for the structure, which end is anchored appropriately to the top surface of board  30 . Extending from this mounting end toward the opposite end, structure  110  includes a springy, longitudinally bendable, reed-like expanse  110   b . The opposite end of structure  110  contains an integral downturned skeg blade  110   c  which moves with non-pivotal arcuate motion with bending of expanse  110   b.    
     An appropriate deployment-adjustment screw  112  is threaded into a suitable accommodating bore provided in expanse  110   b , in such a manner that the lower end of screw  112  can act directly upon the upper surface of board  30  to create a pre-set amount of flex distortion (bend) in expanse  110   b , thus to establish, variably, the nominal downward deployment of the underside of blade  110   c  through the accommodating slot shown at  114  (in FIG. 17) in board  30 . 
     In this reed-like structure, one can see that, effectively, there is a definitive positive-drive connection that exists between blade  110   c  and the reed-like flexure expanse  110   b  in structure  110 . Considering screw  112  along with flexible expanse  110   b , one can see that these two components coact to furnish both nominal deployment adjustment positioning, and yieldable biasing, for blade  110   c.    
     With final attention now directed to FIGS. 21-24, inclusive, these four figures illustrate at  116  another, modified form of an arcuate (but not pivotal), reed-like skeg structure which is similar in many respects to just-described structure  110 . However, with regard to structure  116 , the manner in which nominal deployment is adjusted is a bit different, and there is added structure present which is effective to change the biasing force exerted through the flexible reed portion of the structure on a skeg blade  116   a  which forms part of the skeg structure. Specifically, two adjustment screw mechanisms  118 ,  120  are furnished in structure  116  having elongate adjustment screws with lower ends appropriately carrying slider shoes (also called sliders), such as the sliders shown at  118   a ,  120   a  in FIGS. 23,  24 , respectively. These sliders are slidably received in a somewhat captured condition within an elongate angular track furnished as shown at  117  in the figures. The sliders associated, respectively, with mechanisms  118 ,  120  can be slidably adjusted along the length of track  117 , and once adjusted, locked against further slidable movement through tuning of the adjustment screws within these mechanisms. 
     The slider in mechanism  118  extends laterally into a nip region beneath the flexible reed portion of the overall structure in  116 , and it will be apparent from a look at FIG. 21, that the lateral position along track  117  of this slider, i.e., its position to the left or to the right along track  117 , is effective to produce a bending condition in the skeg flexure region, thus to control the amount of downward nominal deployment of blade  116   a . By loosening the screw in structure  118 , and sliding this structure to the left or to the right along track  116 , a selected deployment condition can be created, and then locked into place so-to-speak by tightening of this screw. 
     Adjustments made in the position along track  117  of the shoe in screw adjustment mechanism  120  effectively lengthens and shortens the active flexure portion of structure  118 , thus to change selectively the biasing force which this flexure portion exerts on blade  116   a.    
     There is thus proposed by the present invention, illustrated in several particularly useful forms, deployable skeg structure for a snow-traveling device of the types generally illustrated and mentioned. Accurate and reliable deployment-control over a skeg blade (movable generally arcuately, pivotally or linearly) is furnished, with a deployed blade being predictably and appropriately-responsive, in a selected, travel-limited manner, to the instantaneous condition of any engaged snow surface. 
     It is believed that the following claims particularly point out certain combinations and subcombinations that are directed to one of the disclosed inventions and are novel and non-obvious. Inventions embodied in other combinations and subcombinations of features, functions, elements and/or properties may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such amended or new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of the inventions of the present disclosure.