Safety athletic pole

An athletic pole including a handle, a s haft, and a handle-to-shaft transition assembly, the transition assembly being adapted for allowing the handle to articulate and for minimizing rotational motion of the handle relative to the shaft during pole operation. The transition assembly includes an enlarged shaft base on the shaft and an enlarged handle base on the handle. The shaft base includes a handle-base-engaging surface, a raised alignment post on the handle-base-engaging surface, axial splines formed with the alignment post, and radial splines extending along the handle-base-engaging surface of the shaft base. The handle base includes a shaft-base-engaging surface having spline grooves complementary to the radial splines and the axial splines of the shaft base. The shaft-base-engaging surface also includes spline groove pairs parallel to and flanking radial portions of the the spline grooves, wherein the spline groove pairs receive the axial splines that flank the particular axial spline received by a radial portion of a spline groove during a particular handle articulation. The handle base also includes axial extensions of the radial portions of the spline grooves that engage the radial splines of the shaft base during handle articulation.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION 
The invention described herein is a safety athletic pole designed for use 
in a variety of athletic activities including, among others, hiking and 
skiing. To maximize clarity but without imposing a limitation, discussion 
of the invention is hereafter directed toward its potential embodiment as 
a ski pole. 
The traditional ski pole is composed of a handle, a long, thin, rigid shaft 
with a pointed tip, and a basket near the tip to restrict snow 
penetration. The ski pole assists skiers in maneuvering efficiently in 
various skiing terrains and under an assortment of snow and terrain 
conditions. While using ski poles, a skier, whether skiing downhill or 
cross country, may sustain significant injuries from the simplest of 
falls. To minimize this danger, novice skiers are taught to release their 
poles or attempt to keep their arms close to their body. Recent ski pole 
handle design attempts to make release easier, but experience indicates 
that, in actuality, little has been done to prevent a number of ski 
pole-related upper extremity injuries. 
When falling, the natural tendency is to hold the poles tighter and brace 
the fall with outstretched arms. The resulting positions put the thumb at 
a significant biomechanical disadvantage. Abnormal forces applied to the 
thumb in this manner often cause injury to the ligamentous tendon complex, 
joint capsule, and bones. One of the most disabling injuries often from 
such a fall is a complete tear of the ulna collateral ligament of the 
thumb. Statistically, this injury ranks as the second most common reported 
injury in skiing (knee injuries ranking first). If one includes unreported 
injuries, it may be the most common injury in skiing. Many skiers we have 
interviewed have spent six to nine months recovering from injured thumbs 
for which they never sought medical attention. At first glance, these 
injuries seem innocuous to those outside of the medical profession. 
Unfortunately, this is not the case. Simple tasks like holding a cup of 
coffee are impossible for most skiers suffering from these injuries. Tasks 
that require motion of a thumb injured in this manner are difficult if not 
impossible to perform. 
The present invention helps prevent these debilitating injuries by 
incorporating an articulated break-over mechanism into the pole design. 
The break-over mechanism allows the pole handle to articulate when an 
abnormally high bending force is applied to the handle, as in an accident. 
The break-over mechanism includes mating handle and shaft bases that are 
radially enlarged relative to the shaft. Prior to and during initial 
handle articulation, this radial enlargement of the mating handle and 
shaft bases enhances pole stability and integrity by distancing the 
fulcrum point of the articulation mechanism from the pole axis. As the 
handle approaches full articulation, the enlarged handle and shaft bases 
further enhance pole stability and integrity by reducing the distance from 
the fulcrum point to the pole axis, thereby reducing spring actuation. 
Both the enlarged handle and shaft bases and the movable fulcrum point 
they provide render the invention both distinguishable from and superior 
to the prior art. 
In addition, the invention improves on similar prior art ski poles by 
providing a system of splines and spline-receiving grooves in the enlarged 
handle and shaft bases that minimizes potential misindexing of the handle 
and pole both when the handle is unarticulated and in all stages of handle 
deflection. 
SUMMARY 0F THE INVENTION 
Therefore, it is an object of the invention to provide an athletic pole 
that provides enhanced user safety. 
It is another object of the invention to provide an athletic pole with an 
articulating break-over feature that permits handle articulation when an 
abnormally high bending force is applied by the user. 
It is another object of the invention to provide an athletic pole that 
permits the user to adjust the tension between the articulating pole 
handle and the pole shaft. 
It is another object of the invention to provide an athletic pole with an 
articulating break-over mechanism that reduces the tension between the 
articulating pole handle and the pole shaft after initial articulation of 
the handle. 
It is another object of the invention to provide an athletic pole with an 
articulating break-over mechanism that maximizes pole stability and 
minimizes pole stress during articulation. 
It is another object of the invention to provide an athletic pole that 
limits rotational motion of the handle relative to the shaft. 
It is another object of the invention to provide an athletic pole with a 
handle and a shaft that retain coaxial orientation when normal bending 
forces are applied to the handle. 
These objects of the present invention are achieved in the preferred 
embodiments disclosed below by providing an athletic pole including a 
handle, a shaft, and a handle-to-shaft transition assembly, the transition 
assembly being adapted for allowing the handle to articulate and for 
minimizing rotational motion of the handle relative to the shaft during 
pole operation. The transition assembly includes an enlarged shaft base on 
the shaft and an enlarged handle base on the handle. The shaft base 
includes a handle-base-engaging surface, a raised alignment post on the 
handle-base-engaging surface, axial splines formed with the alignment 
post, and radial splines extending along the handle-base-engaging surface 
of the shaft base. The handle base includes a shaft-base-engaging surface 
having spline grooves complementary to the radial splines and the axial 
splines of the shaft base. The shaft-base-engaging surface also includes 
spline groove pairs parallel to and flanking radial portions of the the 
spline grooves, wherein the spline groove pairs receive the axial splines 
that flank the particular axial spline received by a radial portion of a 
spline groove during a particular handle articulation. The handle base 
also includes axial extensions of the radial portions of the spline 
grooves. The extensions engage the radial splines of the shaft base during 
handle articulation. 
According to one preferred embodiment of the invention, the radial splines 
are formed with the handle-base-engaging surface and the axial splines. 
According to another preferred embodiment of the invention, the shaft base 
also includes a narrow circumferential annulus for the handle base to seat 
upon during unarticulated operation. 
According to yet another preferred embodiment of the invention, the shaft 
base also includes a ramp to facilitate movement of the handle base onto 
the annulus following handle articulation. 
According to yet another preferred embodiment of the invention, the shaft 
base also includes a rim around the periphery of the shaft base. The rim 
limits the movement of the handle base across the shaft base by forming an 
outer boundary of the handle-base-engaging surface, and, upon release of 
the handle, the rim assists the handle in resuming a normal coaxial 
position relative to the shaft. 
According to yet another preferred embodiment of the invention, the 
handle-base-engaging surface, the shaft-base-engaging surface, the rim, 
and the alignment post are annular. 
According to yet another preferred embodiment of the invention, the handle 
base is conical. 
According to yet another preferred embodiment of the invention, the handle 
base is fixedly secured to the handle. 
According to yet another preferred embodiment of the invention, the spline 
grooves in the shaft-engaging-surface of the handle base comprise radial 
portions, radial-to-axial transition portions, and axial portions. 
According to one preferred embodiment of the invention, an athletic pole 
including a handle, a shaft, and a handle-to-shaft transition assembly, 
the transition assembly being adapted for allowing the handle to 
articulate and for minimizing rotational motion of the handle relative to 
the shaft during pole operation. The transition assembly includes an 
enlarged shaft base on the shaft and an enlarged, conical handle base 
fixedly secured to the handle. The shaft base includes an annular 
handle-base-engaging surface, a raised, annular alignment post on the 
handle-base-engaging surface, axial splines formed with the alignment 
post, and radial splines extending along the handle-base-engaging surface 
of the shaft base and formed with the handle-base-engaging surface and the 
axial splines. The handle base includes an annular shaft-base-engaging 
surface having spline grooves complementary to the radial splines and the 
axial splines of the shaft base. The shaft-base-engaging surface also 
includes spline groove pairs parallel to and flanking radial portions of 
the spline grooves, wherein the spline groove pairs receive the axial 
splines that flank the particular axial spline received by a radial 
portion of a spline groove during a particular handle articulation. The 
handle base also includes axial extensions of the radial portions of the 
spline grooves. The extensions engage the radial splines of the shaft base 
during handle articulation. 
According to yet another preferred embodiment of the invention, the shaft 
base also includes an annular rim around the periphery of the shaft base. 
The rim limits the movement of the handle base across the shaft base by 
forming an outer boundary of the handle-base-engaging surface, and, upon 
release of the handle, the rim assists the handle in resuming a normal 
coaxial position relative to the shaft. 
According to one preferred embodiment of the invention, including a handle, 
a shaft, and a handle-to-shaft transition assembly, the transition 
assembly being adapted for allowing the handle to articulate and for 
minimizing rotational motion of the handle relative to the shaft during 
pole operation. The transition assembly includes an enlarged shaft base on 
the shaft and an enlarged, conical handle base fixedly secured to the 
handle. The shaft base includes an annular handle-base-engaging surface, a 
raised, annular alignment post on the handle-base-engaging surface, axial 
splines formed with the alignment post, and radial splines extending along 
the handle-base-engaging surface of the shaft base and formed with the 
handle-base-engaging surface and the axial splines. The shaft base also 
includes a narrow circumferential annulus for the handle base to seat upon 
during unarticulated operation, a ramp to facilitate movement of the 
handle base onto the annulus following handle articulation, and an annular 
rim around the periphery of the shaft base. The rim limits the movement of 
the handle base across the shaft base during handle articulation by 
forming an outer boundary of the handle-base-engaging surface, and, upon 
release of the handle, the rim assists the handle in resuming a normal 
coaxial position relative to the shaft. The handle base includes an 
annular shaft-base-engaging surface having spline grooves complementary to 
the radial splines and the axial splines of the shaft base. The spline 
grooves include radial portions, radial-to-axial transition portions, and 
axial portions. The shaft-base-engaging surface also includes spline 
groove pairs parallel to and flanking the radial portions of the spline 
grooves, wherein the spline groove pairs receive the axial splines that 
flank the particular axial spline received by a radial portion of a spline 
groove during a particular handle articulation. The handle base also 
includes axial extensions of the radial portions of the spline grooves. 
The extensions engage the radial splines of the shaft base during handle 
articulation.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE 
Referring now specifically to the drawings, an athletic pole product 
according to a preferred embodiment of the invention is illustrated 
broadly at reference letter P in FIG. 1. A conventional long, thin shaft 1 
with a snow-penetrating tip 2 and a penetration limiting basket 3 is 
connected to a handle 4 comprising a handgrip 4A and a handle body 7. The 
connection is accomplished by a spring-loaded articulating joint 5. The 
articulating joint 5 provides a break-over feature that limits the force 
that the ski pole P can apply to the hand, and is the subject of this 
invention. 
A preferred design arrangement that accomplishes the desired objectives is 
shown in FIG. 2, which is a cross-sectional view of the handle 4 of the 
safety ski pole P. Referring now to FIG. 2, a compression spring 6 is 
utilized to provide a seating force between the handle body 7 and a 
matching seat comprising a shaft base 8, which is attached to the shaft 1. 
Coaxial centering of the handle 4 and the shaft 1 under normal loads 
imposed during skiing is accomplished by the matching surfaces and 
features of the handle body 7 and the seat 8, and a restraining rail 
comprising a rim 9 around the perimeter of the seat 8. 
In the embodiment shown in FIG. 2, the compression spring 6 resides in a 
guiding handle cavity 6A in the handle body 7 and its compressive force is 
transmitted from the handle body 7 to the seat 8 and the shaft 1 by 
attachment means comprising a flexible cable 10. The upper end of the 
cable 10 is anchored to a slidable spring cap 11 by means of a cross pin 
12 inserted in a cross hole 13 in the spring cap 11. The cable 10 is 
secured at its lower end by a cross member 14 and a cableend anchor 14A, 
the cross member 14 residing in the holes 14B in the shaft 1 and kept in 
place, in this instance, by a collar 15 of the seat 8. The cross member 14 
extends beyond the outer diameter of the shaft 1 into axial slots 16 in 
the seat 8 in order to radially index the seat 8 to the shaft 1. Other 
means of retention may be used, such as that shown in FIG. 3, which is 
particularly adaptable to small diameter and/or solid shafts. In this 
instance, a cross pin 17A is held in place by a retaining ring 17. Other 
alternatives are to thread or cement the seat 8' to the shaft 1'. 
Referring again to FIG. 2, the level of transverse force that is required 
to be applied to the handle 4 to initiate the breakaway action is a 
function of the combination of the moment arm created by the radial 
dimension of a handle base 22 and the seating force provided by the spring 
6 acting through the flexible cable 10. A practical combination will have 
the diameter of the handle base 22 significantly larger than that of the 
shaft 1 and/or the handle body 7 where it interfaces with the handgrip 4A 
in order for a practical spring 6 to be able to reside within the 
dimensional confines of the handle 4 or the shaft 1. Once the handle base 
22 is selected, various means can be employed to provide the desired 
resistance to articulation by presenting the assembly compression of the 
spring 6. The means employed in the configuration shown in FIG. 2 and FIG. 
2A is to assemble an anchor pin 12 into a selected pair of cross-holes 13, 
13a, or 13b in the spring cap 11. 
As shown in FIG. 2, the handle body 7 is inserted into the handgrip 4A. The 
handgrip 4A, which is customarily a molded elastomer, is held in place by 
a button head screw 18 threaded into a cross member 19 which is inserted 
into the cross holes 20 in the handle body 7 and held in place by the 
handgrip 4A upon assembly. Referring again to both FIG. 2 and FIG. 2A, 
while the handgrip 4A can be held in place by friction or by an adhesive, 
it is convenient to be able to remove it so that the user may adjust the 
handle tension by selecting a different pair of cross holes 13, 13a, or 
13b in the spring cap 11 in which to insert anchor pin 12. 
When the spring tension is adjusted properly, the handle 4 and the shaft 1 
will maintain a coaxial position under normal bending moments imposed by 
the skier's hand, wrist, and arm, as reacted by the shaft 1 against 
normally encountered surfaces. However, if a higher than normal bending 
moment is experienced, for instance as the result of a fall that may trap 
the pole P under the skier's body or under his ski(s), as shown in FIG. 4, 
the handle 4 will pivot with an edge 21 of the handle base 22 forming the 
fulcrum, and a handle-base-engaging surface 24 between the rail 9 and a 
central alignment post 23 of the seat 8 forming the pivot point. When the 
handle 4 moves to a large articulation angle, the handle base 22 slides 
across the handle-base-engaging surface 24 of the seat 8, coming to rest 
against the post 23 of the seat 8, where it remains as the handle 4 
articulates further. The handle base 22 is prevented from moving further 
toward the center of the seat 8 by the combined restraining action of the 
post 23 and the cable 10 as the handle 4 is articulated to extreme angles, 
even beyond 90 degrees. The flared holes 25A in the handle body 7 and the 
seat 8 through which the cable 10 passes are suitably radiused to prevent 
excessive bending stresses in the cable 10, and the small diameter of the 
holes 25A fit closely to the cable 10 to prevent snow from entering the 
handle cavity 6A or a shaft cavity 1A. The spring 6 will be extended 
beyond the initial adjustment extension as a result of the handle 
articulation, but the resulting load on the skier's hand, thumb and wrist 
will not be sufficient to cause injury. Once the handle base 22 rests 
against the post 23, the articulating force significantly reduces, 
becoming much less than the initiating force, as a result of a reduction 
in the moment arm as the edge 21 of the handle base 22 moves toward the 
post 23. 
When the bending moment on the handle 4 is released, it will automatically 
resume its normal position coaxial with the shaft 1. 
The post 23 of the seat 8 is splined, fitting loosely but non-rotatably 
into a similarly splined pocket 25B in the base of the handle body 7. 
Spline grooves 25 in the handle body 7 extend axially the upper end of the 
pocket 25B, then bend around the lower end of the pocket 25B, extending 
radially to the outer diameter of the handle base 22. As the handle 4 is 
articulated relative to the shaft 1, one or more of the splines on the 
post 23 will engage matching spline grooves 25 of the handle base 22 
throughout the range of articulation of the handle 4, thereby resisting 
rotation of one relative to the other. This feature resists misindexing of 
the handle 4 and the shaft 1, each of which may have non-symmetrical 
features that require alignment. Additionally, this prevents twisting of 
the flexible cable 10 that otherwise may result from repeated actuations. 
Another embodiment of the invention with additional features to restrict 
rotation of the handle relative to the shaft is described below relative 
to FIGS. 9, 9A, 10, and 10A. 
FIG. 5 and FIG. 5A show an alternative arrangement for providing spring 
compression adjustment. The flexible cable 26 has an internally threaded 
terminal 27 attached to its upper end. This terminal 27 has a hexagonal 
exterior surface 27A to prevent its rotation in a hexagonal hole 27B in 
the spring cap 28 while permitting axial relative translation as 
determined by the position of an adjusting screw 29, accessed through a 
hole 30. In this embodiment, the compression spring 31 does not have 
squared and ground ends and the spring seats in the spring cap 28 and the 
handle body 32 are configured to fit the plain cut coil ends 26A of the 
spring 31. This causes the adjusting torque to be transmitted from the 
screw 29 to the cable terminal 27 through the hexagonal hole 27B in the 
spring cap 28 through the spring 31 to the handle body 32, thereby 
preventing twisting of the cable 26 during adjustment. For illustrative 
purposes, the spring 31 is shown compressed to the maximum allowable 
initial force setting. 
FIG. 6 shows still another method of providing adjustability of spring 
compression. The flexible cable 33 has an externally threaded terminal 34 
attached to its upper end and extending through the spring cap 35, which 
is retained by an adjusting nut 36. Adjustment of the position of the nut 
36 without twisting the cable 33 is accomplished by holding the terminal 
34 with a screwdriver while turning the nut 36. Access to the terminal 34 
and the nut 36 is provided by removal of a spring-clip retained cover 37. 
FIG. 7 shows an alternate method of joining the handle 4' to the shaft 40. 
The seat 38 includes with a cylindrical projection 39 that pilots inside 
the shaft 40, with the upper end of the shaft 40 seating on the underside 
of the seat 38. The flexible cable 41 is anchored at the lower end by a 
cross member 42 residing in a pair of transverse holes 42A in the shaft 
40. The seat 38 and the shaft 40 are kept in close contact by the tension 
in the cable 41. The cross member 42 is suitably retained transversely; in 
this embodiment, this is achieved by a sheath 43 held in place by an 
elastomeric sleeve 44. 
While the examples shown in FIGS. 2 through 7 have employed a compression 
spring located in the ski pole handle, the objective of this invention can 
be achieved through other combination of spring types and locations, for 
instance: a tension spring located in the handle; a compression spring 
located in the shaft; or a tension spring located in the shaft. 
Additionally, compound springs may be used. An example of an alternate 
spring arrangement is shown in FIG. 8. Referring to FIG. 8, a tension 
spring 45 is utilized to provide a seating force between the handle body 
46 of the handle 4" and the matching seat 47, which is attached to the 
shaft 48. A tension spring 45 is anchored at its lower end by a pin 49, 
which resides in holes 49A in the shaft 48 and is kept in place by, in 
this instance, a sleeve 50. Other means of retention may be used. The 
spring force is transferred to the handle 4" through the flexible cable 
51, which is attached to an anchor member 52 by means of a second pin 53. 
As shown in FIG. 8 and FIG. 8A, the anchor member 52 is kept from rotating 
relative to the handle 4" by a hexagonal portion 54 of the anchor member 
52 that is axially slidable through a matching hexagonal cavity 54A in the 
handle body 46. The axial position of the anchor member 52 is moveable, to 
permit adjustment of the spring tension through use of a screw 55 threaded 
into the anchor member 52. The head of the screw 55 is seated on a second 
anchor member 56, which in turn rests centrally on the handle body 46. 
In a preferred embodiment of the ski pole shown in FIGS. 9, 9A, 10, and 
10A, the seat 8" and handle base 22' include a system of splines and 
spline-receiving grooves for minimizing potential rotation of the handle 
body 7' relative to the shaft (FIGS. 1 through 8) both when the handle 
body 7' is unarticulated and in all phases of handle articulation. Turning 
to FIGS. 9 and 9A, the seat 8" is shown. A plurality of radial splines 60 
are formed with a handle-base-engaging surface 24' of the seat 8". In 
addition, a plurality of axial splines 61 are formed with the alignment 
post 23 and the radial splines 60. The radial splines 60 and the axial 
splines 61 engage spline-receiving grooves in the handle base (FIGS. 10 
and 10A) during handle articulation in order to minimize rotational motion 
of the handle body (FIG. 10A) and the shaft (FIGS. 1 through 8) during 
handle articulation. Other features of the seat 8" serve to stabilize the 
handle body (FIG. 10A) when it is unarticulated and during articulation. 
Specifically, a narrow circumferential annulus 62 is provided in the seat 
8" for the handle base (FIGS. 10 and 10A) to seat upon during normal, 
unarticulated operation. In addition, in one embodiment of the seat 8", a 
ramp 63 is also provided to facilitate movement of the handle base (FIGS. 
10 and 10A) onto the annulus 62 following articulation. 
Turning now to FIGS. 10 and 10A, the handle base 22' of the handle body 7' 
is shown. shaft-base-engaging surface 64 on the handle base 22' features 
spline grooves 25 for receiving the radial splines and axial splines of 
the shaft base (FIGS. 9 and 9A) during handle articulation. The grooves 25 
each have a radial portion 70, a radial-to-axial transition portion 71, 
and an axial portion 72. In addition, axial extensions 65 of the radial 
portions 70 of the spline grooves 25 are formed in the outer periphery of 
the handle base 22'. The axial extensions 65 further guide and stabilize 
the handle body 7' as the handle base 22' engages the shaft base (FIGS. 9 
and 9A) during handle articulation. The shaft-base-engaging surface 64 of 
the handle base 22' also provides spline groove pairs 66 that are parallel 
to and flank the radial portions 70 of the spline grooves 25. The spline 
groove pairs 66 serve to engage the two axial splines formed with the 
alignment post on the shaft base (FIGS. 9 and 9A) that flank any 
particular axial spline engaged by the corresponding radial portion 70 of 
a spline groove 25 on the handle base 22' during a specific handle 
articulation. Like the radial portions 70 of the spline grooves 25, the 
radial-to-axial transition portions 71 of the spline grooves, the axial 
portions 72 of the spline grooves, and the axial extensions 65 of the 
radial portions 70 of the spline grooves 25, the spline groove pairs 66 
are provided to guide and stabilize the handle body 7' as the handle base 
22' engages the shaft base (FIGS. 9 and 9A) during handle articulation, 
thereby minimizing rotational motion of the handle body 7' relative to the 
shaft (FIGS. 1 through 8) during handle articulation. 
A safety athletic pole is described above. Various details of the invention 
may be changed without departing from its scope. Furthermore, the 
foregoing description of the preferred embodiment of the invention and the 
best mode for practicing the invention are provided for the purpose of 
illustration only and not for the purpose of limitation--the invention 
being defined by the claims.