U.S. patent application number 11/375086 was filed with the patent office on 2006-07-20 for pneumatic pogo stick.
Invention is credited to Bruce L. Spencer.
Application Number | 20060160670 11/375086 |
Document ID | / |
Family ID | 26958884 |
Filed Date | 2006-07-20 |
United States Patent
Application |
20060160670 |
Kind Code |
A1 |
Spencer; Bruce L. |
July 20, 2006 |
Pneumatic pogo stick
Abstract
A pneumatic pogo stick is comprised of an elongate cylindrical
housing which forms a cylinder. The housing is formed from a clear
polycarbonate plastic. A top cap is attached to one end of the
housing to form the top of an air chamber. A plastic piston,
slidable within the cylinder, forms the bottom of the air chamber.
An elongate shaft is coupled to the bottom of the piston and is
moveable therewith, extending from the distal end of said housing
as the piston moves within the cylinder. A bottom bracket assembly
is attached to the bottom of the housing and a bushing for
maintaining the lateral position of the shaft relative to the
housing is attached to the bottom bracket assembly. The bushing
prevents the shaft from rotating relative to the housing. User foot
supports are also attached to the bottom bracket for supporting the
feet of the user and handle bars are attached to the top cap for
grasping with the hands of a user.
Inventors: |
Spencer; Bruce L.; (Mission
Viejo, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
26958884 |
Appl. No.: |
11/375086 |
Filed: |
March 14, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10278075 |
Oct 21, 2002 |
7011608 |
|
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11375086 |
Mar 14, 2006 |
|
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60335524 |
Oct 19, 2001 |
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Current U.S.
Class: |
482/77 |
Current CPC
Class: |
A63B 2208/12 20130101;
A63B 25/08 20130101 |
Class at
Publication: |
482/077 |
International
Class: |
A63B 25/08 20060101
A63B025/08; A63B 26/00 20060101 A63B026/00 |
Claims
1. A pneumatic pogo stick, comprising: an elongate cylindrical
housing having a proximal end and a distal end forming a cylinder,
said elongate cylindrical housing formed from plastic; a top cap
attached proximate the proximal end of the housing; a piston
slidable within the cylinder and forming a substantially air tight
chamber between the piston, cylinder and top cap; an elongate shaft
coupled to said piston and moveable therewith extending from said
distal end of said housing; a bottom bracket assembly attached
proximate the bottom of the housing; a guide for maintaining the
lateral position of the shaft relative to the housing as the shaft
moves with the piston; at least one user foot support coupled to
the bottom bracket assembly; and at least one hand grip member
coupled to said top cap.
2. The pogo stick of claim 1, wherein said housing is formed from
an at least partially transparent plastic material to allow viewing
of the piston therein.
3. The pogo stick of claim 1, wherein said top cap is comprised of
an insertion portion and a clamping portion, said insertion portion
configured for inserting into the housing and attaching thereto and
said clamping portion configured for receiving and clamping a
handle member thereto.
4. The pogo stick of claim 3, wherein said insertion portion
includes a plurality of radially spaced bores for receiving a
plurality of threaded fasteners for attaching the top cap to the
housing.
5. The pogo stick of claim 3, wherein said top cap includes at
least one port for receiving a valve mechanism therein to allow
pre-pressurization of the chamber.
6. The pogo stick of claim 1, further including a plate portion
attached to said elongate shaft and said piston is attached to said
plate portion.
7. The pogo stick of claim 1, wherein said piston is formed from
plastic.
8. The pogo stick of claim 1, wherein said elongate shaft has a
non-circular cross-section, and said guide comprises a bushing
having a similarly shaped non-circular bore for receiving the
elongate shaft therein and substantially preventing rotation of the
elongate shaft relative to the bushing.
9. The pogo stick of claim 1, wherein said bottom bracket assembly
and said at least one foot support are integrally formed.
10. The pogo stick of claim 1, wherein said bottom bracket includes
a plurality of radially spaced bores for receiving a plurality of
threaded fasteners for attaching the bottom bracket proximate to
the distal end of the housing.
11. The pogo stick of claim 1, further including an air filter
positioned between the bottom bracket and the piston.
12. The pogo stick of claim 1, further including a resilient pad
for absorbing the shock of the piston against the bottom
bracket.
13. The pogo stick of claim 1, wherein a diameter of said housing
is approximately two inches to four inches in diameter.
14. The pogo stick of claim 1, wherein the compression ratio of the
volume of air in the chamber before it is compressed divided by the
volume of air in the chamber at maximum compression is
approximately 2.5:1 to 4.5:1.
15. A pneumatic pogo stick, comprising: an elongate cylindrical
housing having a proximal end and a distal end forming a cylinder,
said elongate cylindrical housing formed from an at least partially
transparent plastic; a top cap attached proximate the proximal end
of the housing, the top cap having an attachment portion for
attaching to the housing; handle bars attached to the top cap for
grasping by a user; a piston assembly slidable within the cylinder
and forming a substantially air tight chamber between the piston,
cylinder and top cap; an elongate shaft having a non-circular
cross-section coupled to said piston and moveable therewith
extending from said distal end of said housing; a bottom bracket
assembly attached proximate the bottom of the housing; a bushing
attached to the bottom bracket, said bushing defining an aperture
of a non-circular shape similar to that of the elongate shaft for
maintaining the lateral and rotational position of the shaft
relative to the housing as the shaft moves with the piston; a pair
of user foot supports coupled to the bottom bracket assembly; and a
pair of handle bars attached to the top cap for grasping by a
user.
16. The pogo stick of claim 15, wherein said top cap is comprised
of an insertion portion and a clamping portion, said insertion
portion configured for inserting into the housing and attaching
thereto and said clamping portion configured for receiving and
clamping said pair of handle bars.
17. The pogo stick of claim 16, wherein said insertion portion
includes a plurality of radially spaced bores for receiving a
plurality of threaded fasteners for attaching the top cap to the
housing.
18. The pogo stick of claim 16, wherein said top cap includes at
least one port for receiving a valve mechanism therein to allow
pre-pressurization of the chamber.
19. The pogo stick of claim 15, further including a plate portion
attached to said elongate shaft, said piston attached to said plate
portion.
20. The pogo stick of claim 15, wherein said piston is formed from
plastic.
21. The pogo stick of claim 15, wherein said bottom bracket
assembly and said at least one foot support are integrally
formed.
22. The pogo stick of claim 15, wherein said bottom bracket
includes a plurality of radially spaced bores for receiving a
plurality of threaded fasteners for attaching the bottom bracket
proximate to the distal end of the housing.
23. The pogo stick of claim 15, further including an air filter
positioned between the bottom bracket and the piston.
24. The pogo stick of claim 15, further including a resilient pad
for absorbing the shock of the piston against the bottom
bracket.
25. The pogo stick of claim 15, wherein a diameter of said housing
is approximately two to four inches in diameter.
26. The pogo stick of claim 15, wherein the compression ratio of
the volume of air in the chamber before it is compressed divided by
the volume of air in the chamber at maximum compression is
approximately 2.5:1 to 4.5:1.
27. The pogo stick of claim 15, further comprising a U-cup seal
associated with said piston for forming a seal between said piston
and said cylinder.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of application Ser. No.
10/278,075, filed Oct. 21, 2002, which claims the benefit of U.S.
Provisional Application No. 60/335,524, filed Oct. 19, 2001.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention related generally to a pogo stick, and
more specifically, to a pneumatic pogo stick that utilizes
lightweight and durable materials to maximize the performance and
reliability of a pneumatic pogo stick.
[0004] 2. Background of the Invention
[0005] A conventional pogo stick utilizes a coil spring within a
hollow tube housing to create an upward force when compressed by a
user to propel the user in an upward direction. In order to get
more lift than can be provided with a coil spring and without
increasing the weight of the pogo stick itself, it has been
recognized in the art that an air filled cylinder/piston
arrangement can produce increased propulsion or lift for the same
length of stroke. Some have gone so far as incorporating engine
power in order to increase lift and provide a powered jumping
stick.
[0006] Various attempts have been made in the art to provide
pneumatic pogo sticks. For example, PCT Application WO9961111
discloses an air-type pogo stick which includes an air cylinder to
which foot-boards are attached in a body. The air cylinder has a
valve through which a user can regulate air. The pogo stick is
simultaneously worked by both air pressure power and vacuum power
created in the upper and lower part of the piston in the cylinder
respectively when exerted by an outside force. Such a pogo stick,
however, has many shortcomings in both construction and
functionality and fails to address any of the problems encountered
when attempting to use compressed air as a spring, such as
smoothness of rebound.
[0007] A similar dual chamber jumping device is disclosed in U.S.
Pat. No. 4,632,371 in which a working cylinder provides a working
chamber containing a mass of gas. A gas exchange chamber is fixed
with respect to the working cylinder. An exchange passage connects
the working chamber and the gas chamber. A gas exchange valve is
provided in the exchange passage. An exchange operating handle is
provide separate from the plunger. Such a device is overly
complicated and requires multiple complex parts for assembly and
operation. Furthermore, such a device is relatively heavy and
therefor decreases the lift capabilities of such a device.
[0008] Thus, it would be advantageous to provide a pneumatic pogo
stick that is of relatively lightweight construction, durable,
safe, simple, and reliable in operation.
[0009] It would be a further advantage of the present invention to
provide a pneumatic pogo stick that provides a relatively smooth
ride especially at the bottom of the compression cycle to prevent
jarring of the rider.
[0010] It would be a further advantage of the present invention to
provide a pneumatic pogo stick that allows a user to view the
internal components of the pogo stick for verification of the
integrity of the working parts.
[0011] It would be yet a further advantage of the present invention
to provide a pneumatic pogo stick that is capable of smoothly
propelling a user several feet off the ground.
[0012] It would be still a further advantage of the present
invention to provide a pneumatic pogo stick that is easier to
maneuver than other pogo sticks known in the art and that can be
easily adjusted to accommodate users of various weights and
abilities.
[0013] These and other advantages will become apparent from a
reading of the following summary of the invention and description
of the illustrated embodiments in accordance with the principles of
the present invention.
SUMMARY OF THE INVENTION
[0014] The present invention comprises a pogo stick that utilizes a
pneumatic spring. The pogo stick of the present invention includes
a piston/cylinder with user graspable handles attached or coupled
relative to the top of the cylinder and an elongate shaft attached
to the bottom of the piston. When a user compresses air in the
cylinder by jumping on foot supports attached or coupled relative
thereto, the piston compresses air inside the cylinder. Thus,
stepping or jumping on the foot supports pushes the piston upward,
compressing the air inside the cylinder. This compressed air acts
like a spring creating a force on the piston thus forcing the
piston and the attached shaft away from the handles, which in turn
propels the cylinder, the foot supports attached thereto, and,
ultimately, the user.
[0015] Such a pneumatic pogo stick has a potentially higher power
to weight ratio than a comparable coil spring pogo stick. Moreover,
since the air pressure within the cylinder can be adjusted to
accommodate the weight of a particular rider and because the
compressed column of air within the cylinder can create tremendous
force on the piston, the pneumatic pogo stick of the present
invention can be configured to propel an adult user six feet or
more into the air.
[0016] The pogo stick, in accordance with the principles of the
present invention, includes an outer housing which forms the
cylinder. The piston is fitted within the housing and sealed
relative to the inside surface of the housing as with a U-cup seal.
The piston is thus slidable within the housing to form the piston
cylinder arrangement of the present invention. The housing or
cylinder is formed from a plastic tube, such as poly vinyl chloride
(PVC) or polycarbonate. Such materials exhibit properties of
significant tensile and shear strength while being lightweight and
capable of exhibiting such properties when formed into a
thin-walled structure. The top of the cylinder is sealed to allow
the piston to compress an amount of air between the top of the
piston and the top of the cylinder.
[0017] In one embodiment of the present invention, the top of the
cylinder is sealed with a top cap member coupled to the top portion
of the cylinder. Because of the extreme pressures within the
cylinder that may be generated by a user during use of the device,
the top cap is configured to be attached in a manner that securely
secures the top cap to the top of the cylinder.
[0018] Handle bars or other gripping members are secured at or near
the top portion of the cylinder as by coupling to the top cap. Foot
support structure such as foot pegs are attached at or near the
bottom of the cylinder. A shaft fixedly attached to the bottom of
the piston extends out the bottom of the cylinder. A rubber or
urethane pad is attached to the bottom of the shaft. As a user
jumps on the pogo stick of the present invention, the impact
between the ground and the bottom of the shaft forces the piston
toward the top of the cylinder thus increasing the air pressure
within the cylinder. As the air pressure within the cylinder
increases, the user decelerates until the force created by the
compressed air equals the force applied by the user to the foot
pedals and handle bars. Once the user's downward momentum is
stopped, the force generated by the compressed air between the
piston and the top of the cylinder reverses the direction of the
momentum of the user. The compressed air then forces the piston
toward the bottom of the cylinder, rapidly extending the shaft out
the bottom of the cylinder and propelling the user and the pogo
stick.
[0019] While various pneumatic pogo sticks have been attempted in
the art, the pogo stick of the present invention incorporates
various novel features, not the least of which is the use of a
plastic material, such as a PVC or polycarbonate tube, or other
plastic materials known in the art that are strong, durable and
resilient. Such strength, durability and resiliency allow the
cylinder to withstand the rigors of use without significant damage
or failure, including, but not limited to, severe side impact and
high internal pressure. Polycarbonate is a good choice because it
can be formed into the desired shape, has a relatively high tensile
strength and is light weight. Furthermore polycarbonate can be
manufactured in a variety of colors including clear and can be
easily extruded into the desired form. Moreover, such plastic
materials can be made to be clear or at least of limited opacity so
as to allow a user to view the internal workings of the pogo stick,
specifically the piston, seals and other internal components to
evaluate their integrity without having to disassemble the device.
In addition, the use of a clear material for the housing allows the
user to easily evaluate the condition of the inside surface of the
cylinder. Such evaluation would be more difficult if the cylinder
were formed from an opaque material. Those of skill in the art will
appreciate that other materials may also be employed such as
various forms of cellulose acetate butyrate, and carbon
fiber/resin/epoxy combinations.
[0020] The pogo stick of the present invention is designed to be
strong and durable while minimizing weight. In addition, it is
designed to be maneuverable and controllable during use. One
feature that improves maneuverability and control is the use of a
non-circular slider shaft engaging with a non-circular aperture at
the bottom of the cylinder to limit and/or prevent rotation of the
slider shaft relative to the cylinder. In one embodiment, the
slider shaft is comprised of a hollow square tube. In any event,
the slider shaft may comprise various other non-circular
cross-sectional shapes. The square tube engages with a bottom
assembly which is attached to the bottom portion of the cylinder
and includes a bushing that may be formed from strong, low-friction
plastic, having a square hole formed therein for slidably receiving
the slider shaft while limiting rotation of the slider shaft
relative thereto. The engagement of the square slider shaft with
the bushing substantially prevents the slider shaft and thus the
piston from rotating relative to the cylinder, providing greater
control of the pogo stick by the user and preventing lateral wear
of the piston seal that may otherwise be caused by rotational
movement of the piston relative to the cylinder.
[0021] Like the outer housing, the piston body itself may be made
from a plastic material such as an ultra high molecular weight
polyethylene (UHMWPE) or Delrin. Such materials are durable and
provide a surface having a low coefficient of friction so as to
reduce the amount of wear on the inside surface of the cylinder 12
during use. By using the similar types of material for the cylinder
and piston, wear is significantly reduced between the two
components.
[0022] In the case where wear or damage does occur, the piston of
the present invention is configured to be easily replaced. In order
to replace the piston, the bottom assembly, which may be bolted
with threaded fasteners to the bottom portion of the cylinder, is
removed. If necessary, the foot supports are also removed. The
piston with its attached slider shaft can then be removed from the
cylinder. The piston and slider shaft can then be disassembled so
that the piston can be replaced. Other components such as the
slider shaft and bottom bushing can also be replaced in a similar
manner.
[0023] In order to maintain air pressure within the cylinder during
use, the piston is sealed relative to the inside surface of the
cylinder. If even a small amount of air were to escape from between
the cylinder and the piston during operation, the pogo stick would
eventually lose its ability to propel the user. In one embodiment,
a U-cup seal is placed around the piston in a circumferential
groove therein to form a seal between the piston and the
cylinder.
[0024] As the user is propelled off the ground, the compressed air
in the cylinder rapidly forces the piston to the bottom of the
cylinder. The impact between the bottom of the cylinder and an
abutment at the base of the cylinder is softened by use of a shock
absorbing material, such as an elastomer pad. The pad cushions the
piston's impact at the bottom of its stroke. The shock absorbing
pad may be doughnut shaped to fit around the slider shaft and may
be attached to the top of the bushing.
[0025] In another embodiment, a coil spring or other shock absorber
type structures and materials are utilized to reduce the impact
between the piston and the bottom bushing. By preventing direct
contact between the piston and the bottom assembly, the components
will be protected from damage that may otherwise occur.
[0026] In another embodiment, because the motion of the piston
creates a vacuum below it on its upward stroke, it is highly likely
that dust and dirt would be drawn into the cylinder. A dust seal
around the slider shaft may be provided to allow air to flow into
this space.
[0027] Likewise, a chamber or housing may be provided above the
bottom assembly into which an oil/foam air filter is inserted. The
filter material is formed to fit snugly around the slider shaft.
The filter effectively prevents dust and dirt from entering the
cylinder and significantly reduces excess wear and damage that
might otherwise occur.
[0028] The distal end of the slider shaft is provided with a pad,
such as a urethane or rubber pad attached to the bottom of the
slider shaft. The pad softens the initial impact of the end of the
slider shaft with the ground to provide a smoother and less jarring
ride for the user. In addition, the pad provides a ground gripping
structure that allows the user to apply side forces to the pogo
stick without the slider shaft slipping from beneath the user.
Thus, the pad acts as both a cushion as the pogo stick hits the
ground and a ground gripping member to allow the user to increase
maneuverability of the pogo stick without losing control.
[0029] A bottom assembly is attached to the bottom of the cylinder.
This assembly provides an abutment structure at the distal end of
the cylinder for preventing the piston from exiting the cylinder.
The bottom assembly also provides structure for secure attachment
of user foot supports.
[0030] In one embodiment, the top cap is provided with an air valve
for adding air to and releasing air from the air cylinder. The air
valve allows the cylinder to be pre-pressurized before use and to
customize the air pressure to the user's desires. Thus, for
example, for a heavier user, more air can be added before use to
provide sufficient "bounce" of the pogo stick during use for the
particular user. In addition, the air within the cylinder can be
selectively released if it is determined that less air is
desired.
[0031] In order to provide a pogo stick that is comfortable to
operate by an average user while providing the desired bounce in
the device, the dimensions of the various components of the pogo
stick of the present invention have been optimized. That is, for
each rider there is a preferred distance between the hand grips and
the foot pegs for most comfortable operation of the pogo stick.
There is an important relationship between the above mentioned
external dimension and the maximum piston stroke length. For
example, for an average adult rider, a stroke length of the piston
of approximately 14 inches to 20 inches is desired. Longer stroke
lengths mean that the cylinder of the pogo stick must also be
longer causing the pogo stick to become longer and more awkward to
operate.
[0032] The compression ratio of the air cylinder of the pogo stick
also helps to add to or detract from the comfort of use of the pogo
stick. For more comfortable operation, the air cylinder compression
ratios are from approximately 2.5:1 to 4.5:1. This range helps to
provide smooth jumping and landing. Furthermore, it prevents a
"hammering" effect on the user, caused when the air pressure inside
the air chamber ramps up rapidly due to too high of a compression
ratio. The desired compression ratio is achieved by either
increasing the length of the air cylinder or decreasing the piston
stroke. The ratio of piston stroke to cylinder length of the pogo
stick of the present invention is such that this "hammering" effect
is eliminated.
[0033] In one embodiment, the foot pedals include "grinding"
features on their bottom sides. Such "grinder pedals" allow the
user to do tricks that involve sliding on the pedals down various
structures such as metal rails. These pedals may be formed from
metal with plastic inserts on the bottom surface in order to
decrease wear and friction when sliding.
[0034] In another embodiment, a user controllable slider shaft
brake are incorporated. Such a brake allows the user to stop the
motion of the slider shaft by applying a clamping or gripping force
to the slider shaft. In one embodiment, a lever, such as a brake
lever found on a motorcycle is provided on the handlebars for
actuating the brake. The brake allows the user to prevent the
slider shaft from moving relative to the cylinder.
[0035] Thus, the pogo stick of the present invention has
significantly more power than a conventional spring-type pogo
stick, is more maneuverable, allowing the user to perform various
tricks, is durable and relatively light weight, and is configured
to provide a smooth and non-jarring ride for a user of practically
any size and weight.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The foregoing summary, as well as the following detailed
description of the illustrated embodiments is better understood
when read in conjunction with the appended drawings. For the
purpose of illustrating the invention, there is shown in the
drawings several exemplary embodiments which illustrate what is
currently considered to be the best mode for carrying out the
invention, it being understood, however, that the invention is not
limited to the specific methods and instruments disclosed. In the
drawings:
[0037] FIG. 1 is a cross-sectional side view of a first embodiment
of a pneumatic pogo stick in accordance with the principles of the
present invention;
[0038] FIGS. 2A, 2B, 2C and 2D show first and second side views and
first and second top views, respectively, of a first embodiment of
a top cap in accordance with the principles of the present
invention;
[0039] FIG. 3 is an exploded view of a first embodiment of a bottom
bracket and foot peg in accordance with the principles of the
present invention;
[0040] FIG. 4 is a partial cross-sectional side view of a first
embodiment of the bounce pad of a pogo stick in accordance with the
principles of the present invention;
[0041] FIGS. 5A, 5B and 5C are top and side views, respectively, of
a second embodiment of a top cap in accordance with the principles
of the present invention;
[0042] FIGS. 6A, 6B and 6C are top, side, and cross-sectional side
views, respectively, of a third embodiment of a top cap in
accordance with the principles of the present invention;
[0043] FIG. 7A is a partial cross-sectional side view of a second
piston/shaft assembly in accordance with the principles of the
present invention.
[0044] FIGS. 7B and 7C are cross-sectional views of a slider shaft
in accordance with the principles of the present invention
illustrating various geometries and orientations;
[0045] FIGS. 8A and 8B are top and side views of a second
embodiment of a bottom bracket/foot support assembly in accordance
with the principles of the present invention; and
[0046] FIGS. 9A and 9B are top and cross-sectional side views of a
third embodiment of a bottom bracket assembly in accordance with
the principles of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0047] FIG. 1 illustrates a first embodiment of a pneumatic pogo
stick, generally indicated at 10, in accordance with the principles
of the present invention. The pogo stick 10 is comprised of a
plastic tube 12 which forms an outside housing to which various
other components of the device are attached and a cylinder portion
15 of a piston 14/cylinder 15 arrangement. Plastics such as PVC or
polycarbonate are preferable over other materials including steel
and aluminum because they are strong, lightweight, resilient,
inexpensive, and dent resistant. An alternate material that could
be used for the cylinder 12 is cellulose acetate butyrate. Such
plastic materials are preferred since metals such as aluminum or
steel, if dented, may cause the pogo stick to leak air between the
cylinder 15 and piston 14 during use or partially or fully obstruct
movement of the piston 14 relative to the cylinder 15 so that the
device 10 is no longer operable. Thus, despite side impacts, the
cylinder 15 must remain sufficiently round in order for the piston
14 to be able to smoothly travel through it. Because of the nature
of use of such an extreme pogo stick, forming the housing 12 from
an easily deformable, less resilient material may limit the life of
the pogo stick.
[0048] The pogo stick 10 of the present invention is configured to
accommodate various sizes and weights of users and to propel the
user several feet in the air. For example, assuming that the
maximum weight of a user is about 250 pounds and that the maximum
"g" load that could be exerted would be about 4 g's (A "g" being a
measurement of acceleration where 1 g equals the acceleration of
gravity). For a 250 lb. user, 4 g's results in a 1000 lb. force or
maximum load. To keep the maximum operating air pressure within the
cylinder 15 at about 150 psi, the top surface of the piston 14
would have an area of approximately 7 sq. in. or larger (1000 lbs
divided by 150 psi. equates to 6.67 sq. in.). A 3 inch diameter
cylinder 12 has an area of approximately 7 sq. in. In order to
provide a safety factor, the cylinder 15 may be provided with a
3.25 inch inner diameter. Using a 3.25 inch inner diameter cylinder
15 provides a piston 14 area of approximately 8 sq. in. For a
smaller user, such as a child, the diameter of the cylinder 15 may
be two inches or less. Likewise, for more extreme riding and or
larger adult riders, the diameter of the cylinder 15 may be four
inches or more.
[0049] The thickness of the walls of the housing 12 is dependent on
the type of material being used for the housing 12. The housing 12
must be able to at least withstand the 150 psi internal pressure,
as well as the all of the various impacts and stresses that the
pogo stick 10 experiences during use. For a polyethylene or
polycarbonate housing 12, an optimal wall thickness would be about
1/8 inch. Another factor in constructing the housing 12 is to
determine an appropriate length. In order to accommodate an average
user, the length of the housing 12 should not be too long or too
short. For a rider who is approximately 5 ft. 10 inches tall, the
length from foot supports 34' and 34'' to a hand grip member 20 is
about 30-34 inches. If the housing 12 is to be fitted between the
foot supports 34' and 34'' and the hand grip member 20, the length
of the housing 12 should be about 32 inches long. This length of
the housing 12 allows the hand grip member 20 to be positioned
proximate the top of the housing 12 and the foot supports 34' and
34'' positioned near the bottom of the housing 12. In addition,
such distance between the foot supports 34' and 34'' and the hand
grip member 20 provides a comfortable position for the user when
riding the pogo stick 10. While it is contemplated that longer or
shorter lengths of the housing 12 could be utilized, the use of a
significantly longer housing 12 may prevent the user from leaning
over the top of the handle grip member 20 to use his/her upper body
weight to apply force to the pogo stick 10 or may extend a slider
shaft 18 below the foot supports 34' and 34'' a distance that makes
it difficult for the user to initially get on the pogo stick
10.
[0050] It is further contemplated that the foot supports could be
configured to be vertically adjustable relative to the longitudinal
axis of the pogo stick 10. That is, to better accommodate riders of
various heights, the foot supports 34' and 34'' could be indirectly
coupled to the bottom bracket 32. For example, an outer sleeve or
bracket assembly (not shown) attached to the bottom bracket 32 may
provide multiple attachment points along a length thereof for
attachment of the foot supports 34' and 34'' at discrete locations
relative to the length of the housing 12. Likewise, a riser (not
shown) could be attached to the top cap to which the handle bars
could be attached to increase the distance between the top cap and
the foot supports. As such, the distance between the foot supports
34' and 34'' and the handle grip member 20 may be increased or
decreased depending upon the height of the user and the user's
comfortable riding position. Likewise, the handle grip member 20,
which is illustrated as being an elongate, generally straight
length of material may be replaced with a handle member (not shown)
that is configured more similarly to those found on bicycles. That
is, the handle member could have a curved or arched center portion
with raised gripping portions that extend above the point of
attachment to the top of the pogo stick 10. Such a handle bar
arrangement could thus be utilized to increase the effective
distance between the handle grip portion and the foot supports or
pedals 34' and 34'' to accommodate taller riders.
[0051] Compression ratio is the ratio of the volume of the air
before it is compressed, divided by the volume of the air after it
is compressed. The maximum compression ratio is, therefore, a
function of the maximum stroke length and the length of the dead
space that is within the cylinder 12. FIG. 1 shows the piston 14 at
the top of its maximum stroke and (in dashed lines) at the bottom
of its stroke. The length of stroke is in part dependent upon the
total length of the cylinder 15. To a large extent, the desired
length of the pogo stick 10 is what determines the length of the
cylinder 12, which in turn effects the diameter of the cylinder 15
to provide the desired riding characteristics of the present
invention.
[0052] The diameter of the cylinder 12 is based on ease of use, or
more specifically, smoothness of ride and the desired feel of
"springiness" generated by the compression of air in the cylinder
15. The larger the diameter of the cylinder 15, the lower the
operating pressures will be. Thus, it is desirable to make the
diameter of the cylinder 15 as large as possible without making the
pogo stick 10 too awkward to operate.
[0053] As the compression ratio is dependent on the stroke length,
the length of the slider shaft 18, which is attached to the piston
14 and extends from the housing 12, must be sufficient to achieve
the desired compression ratios. While the maximum possible
compression occurs when the shaft 18 is forced as far into the
housing 12 as possible, the insertion of the shaft 18 is limited by
the amount of compression generated by the particular user. Thus,
the shaft 18 should be sufficiently short to allow the shaft 18 to
travel into the housing 12 without allowing the piston 14 to
contact a top cap 24, which defines the top of the cylinder 15. The
distance between the top cap 24 and the piston 14 at the top of its
maximum stroke is the "dead space" 13. The smaller the dead space
13, the higher the maximum compression ratio.
[0054] The length of the shaft 18 should not be so long that it
causes too high of a maximum compression ratio or that a user
cannot easily reach the foot supports 34' and 34'' when attempting
to get onto the pogo stick 10. Too long of a slider shaft 18 also
makes the pogo stick 10 difficult to control placing the center of
gravity of the user too high off the ground.
[0055] In this embodiment, the top of the cylinder 12 is sealed by
the cap 24 that is bolted or otherwise mechanically, adhesively or
chemically attached as by welding proximate the top 25 of the
housing 12. The cap 24 has an insertion portion 27 that fits
tightly inside the housing 12. The cap 24 also has a lip 29 that is
the approximately the same thickness as the housing wall. This lip
29 allows the cap 24 to be properly inserted into the housing 12
during assembly as the lip 29 abuts with the top of the housing 12
when the cap 24 is fully inserted therein. The top cap 24 of the
housing 12 must be sufficiently secured within the housing 12 so as
to be able to withstand the pressure from the compressed air in the
cylinder 15 when it is compressed by the piston 14. An `O` ring 26
in the insertion portion 27 of the top cap 24 creates an airtight
seal between the housing 12 and the top cap 24, with the top cap 24
and piston 14 forming a compression chamber 17.
[0056] The handle bar 20 of the pogo stick 10 is attached by a
clamp 31 that is incorporated into the top cap 24. The handle bar
20 consists of an aluminum or stainless steel tube with hand grips
20' and 20'' on both ends that extend beyond the clamp 31 of the
top cap 24. The base portion 33 of the top cap 24 which includes
the insertion portion 27 is bolted as with threaded fasteners as
shown through the wall of the housing 12 and into the insertion
portion 27. While only two threaded fasteners or bolts are shown,
there are actually a plurality of such fasteners radially disposed
around the housing 12 to provide multiple points of attachment
between the housing 12 and the top cap 24 to ensure that the top
cap 24 cannot dislodge from the housing 12.
[0057] At the distal end of the housing 12 is the bottom assembly,
generally indicated at 36. The bottom assembly 36 provides four
basic functions. First, the bottom assembly 36 provides an abutment
for preventing the piston 14 from exiting the distal end of the
housing 12, as when the piston 14 is in the position shown in
dashed lines. Second, the bottom assembly 36 provides structure for
attaching the foot supports 34' and 34'' relative to the housing
12. Third, the bottom assembly 36 provides a bearing surface for
maintaining proper longitudinal alignment of the slider shaft 18 as
the piston 14 moves within the cylinder 15. Fourth, the bottom
assembly provides an air filtration system to filter out dust and
other particulates from entering the cylinder 15 through the distal
end of the housing 12. Such contaminates may otherwise form
abrasives in any lubricant utilized to reduce friction between the
piston 14 and cylinder 15 and thus may effect the operation of the
piston/cylinder arrangement of the present invention.
[0058] The bottom assembly 36 includes a bottom bracket 32 having
an insertion portion 37 similar to that of the top cap 24. The
bottom bracket 36, however, has a hollow cylinder configuration for
receiving and maintaining a slider shaft bushing 38. The bushing 38
defines a central aperture 39 for receiving the slider shaft 18 and
defines a guide for the slider shaft 18 as it moves into and out of
the device. Moreover, because the slider shaft 18 has a
non-circular cross-section, forming the aperture 39 of a similar
shape will prevent the slider shaft 18 from rotating relative to
the bushing 38. Furthermore, because the bottom bracket 32, bushing
38 and housing 12 are bolted together with a plurality of threaded
fasteners, as shown, the bushing 38 is prevented from rotating
relative to the housing 12. It is desirable, in accordance with the
principles of the present invention, to prevent any substantial
rotation of the slider shaft 18 relative to the housing 12 as the
distal end of the slider shaft 40 carries the bounce pad 41. The
bounce pad 41 is the primary contact the user has between the pogo
stick 10 and the ground or riding surface. By preventing rotation
of the slider shaft 18, and thus the bounce pad 41, relative to the
housing 12 and thus the handle bar 20, the rider will have more
control over his or her movement by eliminating a rotational degree
of freedom that would otherwise be present if the slider shaft were
circular in cross-section. In addition, prevention of rotation of
the slider shaft 18, which is coupled to the piston 14, prevents
rotation of the piston 14 relative to the cylinder 15. Such
rotational movement of the piston 14 relative to the cylinder 15
may otherwise cause additional wear between the piston and cylinder
that would decrease the life of the device 10.
[0059] As discussed, the engagement of the external features of the
slider shaft 18 with the bushing 38 substantially prevents rotation
of the shaft 18. In addition, the bushing 38 is fixedly mounted
relative to the housing 12 so as to prevent rotation of the bushing
38 relative to the cylinder 12. This may be accomplished by bolting
the bushing 38 into the aluminum sleeve of the bottom assembly.
Another means of securing the bushing 38 to the bottom assembly may
be to provide external threads on an exterior surface of the
bushing 38 and internal threads on an interior surface of the
aluminum sleeve. The bushing 38 could then be threaded into the
sleeve and, if necessary, pinned in place. The bushing 38 is formed
from a material that has a relatively low coefficient of friction
and that is resistant to wear. By having a relatively low
coefficient of friction, the slider shaft 18 can easily glide or
slide through the bushing 38. In addition, as previously discussed,
the bushing 38 keeps the slider shaft 18 from rotating, and as such
there may be many instances during use in which the slider shaft 18
is applying significant side lateral force to the surface of the
bushing 38. If the slider shaft 18 were to significantly grind
against the bushing 38, the bushing 38 would wear over time,
increasing the size of the slider hole therein such that the slider
shaft 18 would be able to move laterally relative to the bushing
38. By providing a low friction surface and being formed from a low
wear material, the life of the bushing 38 will be significantly
increased requiring less frequent replacement, if any.
[0060] The foot supports 34' and 34'' are fastened to the bottom
bracket 32 as with elongate bolt members.
[0061] Positioned on the top of the bottom bracket 32 and bushing
38 is a doughnut shaped air filter 42. The air filter 42 may be
formed from any fibrous material such as a felt-type pad that is
capable of trapping dirt and dust entering the housing 12 through
the aperture 39 of the busing 38. On top of the air filter 42 is a
shock absorbing pad 44, such as an elastomer pad, of a similar
doughnut shape for receiving the slider shaft therethrough. A coil
spring or other shock absorber type structures and materials may
also be employed. By preventing direct contact between the piston
14 and the bottom assembly, the components will be protected from
damage that would otherwise occur. The filter 42 and pad 44 become
sandwiched between the bottom surface of the piston 14 and the top
of the bottom bracket 32 and bushing 38 when the piston 14 is at
the bottom of its stroke, as shown in dashed lines. The pad 44 thus
helps absorb the impact between the piston and the bottom assembly
36 to prevent damage to the various assemblies and provide a more
comfortable feel to the pogo stick 10.
[0062] As discussed, the air is compressed in the cylinder 15 as
the piston 14 moves toward the top cap 24. The piston 14 is
cylindrically shaped and slightly smaller than the inside diameter
of the cylinder 15. The piston 14 may be formed from plastics such
as Ultra High Molecular Weight Polyethylene or Delrin. Such
materials have relatively low coefficients of friction, high
corrosion resistance, and good durability. The plastic on plastic
combination of the piston 14 and the cylinder 15 creates a smoothly
sliding interface allowing the piston 14 to slide along the
cylinder 15 without significant wear of either component. It is
also necessary to lubricate the inside of the cylinder 15 to reduce
wear and to help seal the piston 14 relative to the cylinder
15.
[0063] The piston 14 has a circumferential groove 42 formed in its
outer surface to hold a U-cup seal 43. The seal 43 can be made of
Buna-N rubber, or other materials known in the art, and creates an
airtight seal between the edges of the piston 14 and the walls of
the cylinder 15. The seal 42 allows the piston 14 to compress the
air in the cylinder 15 against the top cap 24. As previously
mentioned, a lubricant helps to form an airtight seal between the
seal 43 and the cylinder 15.
[0064] The piston 14 of the present invention is configured to be
easily replaceable, as may be desirable if it becomes damaged or
excessively worn. In order to replace the piston 14, the bottom
assembly, which is bolted with threaded fasteners to the bottom
portion of the housing 12, is removed. If necessary, the foot
supports are also removed. The piston 14 with its attached slider
shaft 18 is then slid from the housing 12. The piston 14 and slider
shaft 18 are then disassembled so that the piston 14 can be
replaced. Other components such as the slider shaft 18 and bottom
bushing 36 can be replaced in a similar manner. To reassemble the
pogo stick, the slider shaft 18 and piston 14 are reinserted into
the housing 12 and the bottom assembly and foot supports
reattached.
[0065] In order to maintain air pressure within the cylinder 12
during use, the piston 14 is provided with a seal relative to the
inside surface of the cylinder 15. As previously discussed, if air
were to escape from the cylinder 12 during operation, the pogo
stick would lose its ability to propel the user. Thus, a U-cup seal
43 provides a substantially airtight seal around the piston 14.
With the seal 43 in place, a compression chamber 17 is created
between the piston 14 and the top cap 24.
[0066] As the various components are configured to be relatively
easily disassembled for replacement of parts if necessary and while
the seal 43 is designed to be long wearing, it may also be
replaced. The seal 43 is replaced in much the same manner that the
piston 14 is replaced. As discussed herein, the piston 14 is
removed from the housing 12. Once the piston 14 is outside of the
housing 12, the old seal 43 is removed and a new seal then put in
place. The piston 14 can then put back in the housing 12 as is done
when replacing the piston 14. Materials for the seal 43 would
include rubber, EPDM, Neoprene, Silicone, Viton, PTFE, and
Polyurethane. It is preferable that any such seal 43 be long
wearing, resistant to UV exposure, as the housing 12 may be a clear
or only partially opaque material, and easily replaceable.
[0067] As the user bounces in an upward direction, the piston 14
moves toward the bottom of the cylinder 15. In one example, the
piston 14 has a maximum stroke length of approximately 18 inches
and there is a dead space of approximately 8 inches at maximum
stroke. This creates a compression ration of 3.25:1 which provides
a relatively smooth ride for the user. Since pressure increases
inversely relative to volume, at higher compression ratios, e.g.
8:1, the pressure increases rapidly as the piston 14 compresses the
air into a much smaller space. The resulting load doubles in the
last 2 inches of travel. The result is that the rapid increase in
load at the top of the stroke has a "hammering" effect on the
rider, with a great force being generated to reverse the travel of
the piston 14 and rider over a very short distance. This reversing
force acts abruptly over a very short distance and then
deteriorates rapidly.
[0068] A cylinder having an inner diameter of 3 inches to 4 inches
is optimal for an adult version of the pogo stick. If the inner
diameter were significantly smaller, then the pressure within the
air cylinder would have to be proportionately increased to maintain
the spring force of the pogo stick. Such an increase in pressure
can produce the undesired "hammering" effect as well as requiring
other modifications to the device, such as thicker walled materials
to form the cylinder, in order to accommodate such higher
pressures.
[0069] The maximum stroke length is about 14 to 18 inches for a
majority of users. A maximum stroke length of the piston 14 and
slider shaft 18 greater than 20 inches would make the pogo stick
more difficult to operate. In order to harness the pressure built
up in the cylinder 15, the piston 15 is attached to the slider
shaft 18. The slider shaft 18 is the telescoping part of the pogo
stick and moves up and down along with the motion of the piston 14.
The bottom of the piston 14 has a square hole formed therein as by
molding or machining. The slider shaft 18 fits into this hole and
then is bolted or otherwise attached to the piston 14 as with a
shoulder bolt that runs across the diameter of the piston 14 and
nyloc nut. Preferably, the slider shaft 18 is made out of Chrome
Moly (4130) or stainless steel tubing having a substantially square
or hexagon cross-section of approximately 1.25 inch. Such materials
have high strength to weight ratios. The slider shaft 18 thus
protrudes from the bottom of the piston 14 and extends through the
bottom bracket assembly. The bounce pad 41 formed from a material
such as urethane rubber is attached to the distal end of the slider
shaft 18.
[0070] Thus, forcing the shaft 18 into the housing 12 causes the
piston to compress air in the cylinder 15 to create an air spring.
The higher the psi, the larger the return force of the shaft 18 and
the higher the user will be propelled. In addition, the
non-circular shape of the shaft 18 and its engagement with the
bottom bracket bushing 38 allows the user to apply a torque to the
pogo stick since the slider shaft 18 cannot rotate relative to the
housing 12 of the pogo stick 10. This allows for more control by
the user. If the user inputs a rotational motion to the pogo stick,
the entire pogo stick will rotate allowing the user to perform
various tricks that may otherwise be difficult if the shaft 18 were
allowed to rotate relative to the cylinder 12.
[0071] FIGS. 2A, 2B 2C and 2D show a detailed view of one
embodiment of a top cap, generally indicated at 124, in accordance
with the principles of the present invention. The top cap 124 may
be formed from aluminum or other suitable materials known in the
art, such as a material similar to or the same as the material used
for the housing. The top cap 24 consists of a cylindrical bottom
insertion portion 125 with an O-ring groove 126 that plugs into and
seals the top end of the housing. It is attached to the housing by
use of a plurality of button head machine screws equally spaced
around the circumference, for example eight. The handle bar is
inserted into the circular aperture 126 in the upper portion of the
top cap 124 and is held in place by means of an integral clamp 128
that is tightened by two cap screws 130 and 131. The handle bars
are preferably formed of lightweight aluminum tubing, similar to
that used for bicycle handlebars, or thin-wall stainless steel
tubing. Such handle bars give the user significant control over the
pogo stick during use. Also included in the top cap 124 is a
pressure gauge 50, fill valve 48, check valve and bleed valve
46.
[0072] In order to increase the stiffness of the pogo stick, the
cylinder may be pre-pressurized by pumping air into the compression
chamber. Air is added to the cylinder through a valve 46, such as a
typical tire valve stem, attached or coupled to the top cap 124 and
in fluid communication with the compression chamber. Air may be
added by a bike pump, air compressor, or other means, until the
pressure inside the cylinder reaches a desired level. This pre-load
serves to create a stiffer "spring" and allows the user to gain
more height on his/her jumps. In addition, the pre-load also helps
to decrease the possibility of the aforementioned "hammering"
effect.
[0073] The air valve 46 allows adding air to and releasing air from
the air cylinder. The air valve 46 allows the cylinder to be
pressurized before use to customize the air pressure to the user's
desires. Thus, for example, for a heavier user, more air can be
added before use to provide sufficient "bounce" of the pogo stick
during use for the particular user. In addition, the air within the
cylinder can be selectively released if it is determined that less
air is desired. This is preferably allowed by a user activated
bleed valve 48 that is incorporated into or attached to or near the
handle bars. Thus, excess air pressure within the cylinder can be
selectively released "on the fly." This allows the user to reduce
the "spring" of the pogo stick while in motion if it is determined
that the cylinder is over pressurized.
[0074] The preferred embodiment of the pogo stick includes a
pressure gauge 50 in the top cap, thus allowing the rider to
observe the pressure within the cylinder 12. Air pressure within
the cylinder 12 reaches the gauge 50 after passing through a check
valve 52. This check valve 52 assures that the pressure gauge 50 is
not subjected to continual increases and decreases in pressure as
the rider bounces on the pogo stick. It also allows the rider to
determine the maximum pressure attained while jumping. The
aforementioned bleed valve 48 is situated so as to relieve the
pressure between the check valve 52 and the pressure gauge 50.
[0075] Since the air is already under pressure, it does not
compress as rapidly and provides a smoother ride. The ability to
set the pressure in the cylinder also makes it so that the pogo
stick can be used by people of different weights. It allows, in
essence, the stiffness of the spring to be changed. A stiffer
spring or more pre-load pressure will be used for heavier riders
and less pre-load pressure will be used for lighter riders.
[0076] A desired pre-load for adult users may be in the range of
15-50 psi. Once the user is done with the pogo stick for the day,
the bleed valve 48 can be used to release the air within the air
chamber so that the slider shaft can be inserted into the cylinder
for storage of the pogo stick thus decreasing the overall length of
the device.
[0077] As shown in FIG. 3, a bottom bracket assembly, generally
indicated at 200, includes a bottom bracket 232, formed from such
material as aluminum. The bottom bracket 232 is a hollow
cylindrical member with an insertion portion 233 configured to fit
at least partially within the housing. A lip 235 on the bottom
bracket 232 abuts against the bottom of the housing. The bottom
bracket assembly 200 is bolted to the housing. The bottom bracket
232 is formed to receive a UHMW or other plastic bushing 236
therein. The bushing 236 fits relatively snugly within the bottom
bracket 232 and is held in place by the foot peg bolts 242. The
bushing 236 is secured to the bottom bracket 232 so as to prevent
it from rotating and to carry the forces applied to it by the
slider shaft. The bushing 236 has a hole 237 formed therein, in
this case a substantially square hole, to receive the slider shaft
in a manner that substantially prevents rotation of the slider
shaft relative to the bushing 236. As the slider shaft slides
against the bushing 236, the plastic on metal surface creates a
very smooth bearing surface while minimizing wear of the slider
shaft. While not necessary, if desired, a lubricant may be placed
on the slider shaft.
[0078] Because the motion of the piston creates a vacuum below it
on its upward stroke, it is highly likely that dust and dirt would
be drawn into the cylinder. A dust seal around the slider shaft may
prevent this occurrence. However, since the slider shaft is not
round, an effective dust seal would be difficult to form.
Therefore, a chamber or housing is provided above the bottom
assembly into which an oil/foam air filter is inserted. The filter
material is formed to fit snugly around the slider shaft. This
effectively prevents dust and dirt from entering the cylinder and
eliminates the excess wear and damage it might cause. Thus, an air
filter housing 230 is coupled to the insertion portion 233 of the
bottom bracket 232 and is configured for receiving an air filter
insert 231 therein. The air filter insert 231 is formed from a
cylindrical foam pad with a square hole 239 for receiving and
fitting around the slider shaft. The air filter insert 231 is
positioned within the air filter housing 230.
[0079] A shock absorbing pad 228 is positioned on top of the air
filter housing 230 for absorbing the shock of the piston at the
bottom of its stroke.
[0080] The foot pedals 234 are attached to the bottom bracket 232
and busing 236 with elongate bolts 242 that inserted through the
foot pedals 234 and threaded through the bottom bracket 232 and
busing 236. The inside surface 243 of the foot pedal 234 is
contoured to substantially match the contour of the outside surface
of the bottom bracket 232. As such, the foot pedal 234 is
substantially prevented from rotating relative to the bottom
bracket 232 for providing a stable foot support for the rider. The
foot support or pedal 234 is bolted with bolt 242 into the bottom
bracket 232. The pedal 234 is prevented from rotating relative to
the bolt 242 by means of the concave edge on the attaching side.
The foot pedal 234 can be made of a variety of materials and in
various shapes and sizes to fit the particular needs of the user.
Some may have concave arched undersides made of plastic for
"grinding."
[0081] Also, by coupling the bushing 238 to the bottom bracket 232
with the bolt 242, the bushing 236 is prevented from rotating
relative to the housing and thus can prevent rotation of the slider
shaft relative thereto.
[0082] As shown in FIG. 4, the bottom 250 of the slider shaft 218
is provided with a bounce pad 238. The bounce pad assembly 238
consists of a metal bolt portion 252 with a large round head
portion or insert 256. A urethane rubber pad 238 is bonded or
mechanically attached to the insert 256. The threaded portion 252
of the bounce pad assembly 238 engages with internal threads 258
provided in a metal insert 260 attached to the distal end or bottom
250 of the slider shaft 218. The bounce pad 238 can then be
attached to the slider shaft 218 by threading the bolt portion 252
into the insert 260. Furthermore, by making the bounce pad 238
detachable, it may be easily replaced if necessary as may be the
case when the pad 238 becomes excessively worn.
[0083] The pad 238 softens the initial impact of the end of the
slider shaft 218 with the ground to provide a smoother and less
jarring ride for the user. In addition, the pad 238 provides a
ground gripping structure like the tires on a car that allows the
user to apply side forces to the pogo stick without the slider
shaft 218 slipping from beneath the user. Thus, the pad 238 acts as
both a cushion as the pogo stick hits the ground and a ground
gripping member to allow the user to increase maneuverability of
the pogo stick without losing control. This bounce pad 238 is long
wearing and easily replaceable. Long wearing is an important trait
because the pogo stick is designed to be used outdoors on surfaces
that are very abrasive, such as concrete and asphalt. If the
material used for the bounce pad 238 is too soft, it would wear
away more quickly, requiring more frequent replacement. There is a
tradeoff, however, in that the pad 238 should be soft enough to
provide sufficient cushion for the user during use of the pogo
stick. As such, there is some wear when the pad impacts and moves
along the ground.
[0084] FIGS. 5A, 5B and 5C illustrate another embodiment of a top
cap, generally indicated at 300 in accordance with the principles
of the present invention. The top cap 300 is similar in
configuration to the top cap illustrated in FIGS. 2A-2D, but is of
a two piece construction. The top cap 300 includes an cylinder
insertion section 302 and a handle bar clamping section 304. The
insertion section 302 is a generally cylindrical member defining a
circumscribing sealing groove 306 for receiving a sealing member.
The bottom surface of the insertion section 302 defines the top of
the cylinder and defines a semi-spherical recess 308. The clamping
section 304 is attached to the insertion portion with a plurality
of externally threaded fasteners or bolts that are threadedly
inserted into threaded bores 310, 311, 312 and 313 that extend
through the two sections 314 and 316 of the clamping section 304
and into the insertion portion 302.
[0085] The clamping section 304, defined by the two clamping
members 314 and 316 define a transversely extending channel 320 for
receiving the handle bars. The engaging surfaces between the
members 314 and 316 abut one another along one side of the channel
320. On the other side of the channel, the engaging surfaces 322
and 324 define a gap therein between. As the bolts are tightened
around the handle bars, this gap 326 will close to cause a clamping
force around the handle bars.
[0086] A fill/bleed valve port 330 is in fluid communication with
the surface 308 so as to be in fluid communication with the
cylinder of the pogo stick. The use of two pieces as illustrated
provides components that are easily machinable and easily assembled
into the top cap 300 as illustrated. The insert section 302 is
provided with a plurality radially spaced bores, such as bore 332
for receiving threaded fasteners therein and attaching the top cap
300 to the housing of the pogo stick of the present invention.
[0087] FIGS. 6A, 6B and 6C illustrate yet another embodiment of a
top cap, generally indicated at 400 in accordance with the
principles of the present invention. The top cap 400 is similar to
the top cap of FIGS. 5A-5C, but is formed from a single, integral
component. The top cap 400 includes an insertion portion 402 and a
clamping portion 404. The clamping portion 404 defines a laterally
extending gap 406 that is in communication with a transversely
extending channel 408 for receiving handle bars. The gap 406 is
closed with fasteners (not shown) that are inserted into bores 410
and 412 and engage with threaded bore 414. A port 416 is provided
for receiving a schrader valve or other similar valves known in the
art. An o-ring groove 418 is also provided for receiving a sealing
member to seal the insert portion 402 to the housing of the pogo
stick. A plurality of radially spaced internally threaded bores,
such as bore 420 is also provided to attached the top cap 400 to
the housing of the pogo stick.
[0088] As shown in FIGS. 7A, 7B and 7C, a piston/shaft assembly,
generally indicated at 500, in accordance with the principles of
the present invention, is comprised of a piston member 502 and a
slider shaft assembly 504. The piston member 502 is comprised of a
cylindrically shaped member, formed from a material such as
ultra-high molecular weight polyethylene. A circumferential groove
506 for receiving a U-cup seal 508. A central bore 510 is
configured for receiving a socket head cap bolt 512 to attach the
shaft assembly 504 to the piston member 502.
[0089] The shaft assembly 504 is comprised of a circular or disk
shaped plate portion 514 and a tube or shaft portion 516. The shaft
portion 516 may be attached to the plate portion 514 as by welding
with a weld 518. The plate portion 514 is center drilled and tapped
to receive the bolt 512. An o-ring 520 may be placed on the bolt
512. The bolt 512 is then inserted through the piston portion 502
and threaded into the tapped hole 522. The bolt 512 holds the
piston member 502 onto the plate 514 of the slider shaft 516. In
addition, the use of a plate 514 to transfer the impact forces from
the slider shaft 516 to the piston member 502 distributes such
forces over a larger surface area of the bottom surface of the
piston member 502 in increase the reliability of the piston member
502 and the life thereof.
[0090] As illustrated in FIGS. 7B and 7C, the cross-sectional
configuration of the slider shaft 516 may be of a hexagonal shape
as shown in FIG. 7B or a square shape as shown in FIG. 7C. In
either case, the orientation of the shape may be positioned at
various angles relative to the foot pedals of the device. It is
further contemplated that other non-circular cross-sectional
shapes, both symmetrical and asymmetrical may also be employed.
[0091] Referring now to FIGS. 8A and 8B, there is shown a foot
pedal/bottom bracket assembly, generally indicated at 600, which
may be formed from an integral piece of machined aluminum or cast
or molded materials known in the art. The foot pedals 602 and 604
are thus integrally formed with the bottom bracket assembly 606.
The bottom bracket assembly or portion 606 is configured similarly
to other embodiments described herein and can be configured to
accommodate a square slider shaft or a hexagonal slider shaft. The
bracket assembly 606 is provided with a plurality of radially
spaced bores, such as bore 614 for attaching the bottom bracket 606
to the housing of the pogo stick. A bushing 616' or 616'' is
coupled to the bracket assembly 606 so as to receive the slider
shaft as discussed with reference to other embodiments herein, with
the bushing 616' configured for receiving a square slider shaft and
the bushing 616'' configured for receiving a hexagonal slider
shaft.
[0092] The foot pedals 602 and 604 are each provided with curved
surfaces 620 and 622, respectively, on the bottoms thereof to
provide the ability of the user riding the pogo stick to do various
other extreme maneuvers, such as grinding and the like. Thus, the
foot pedals of the present invention may include "grinding"
features on their bottom sides. Such "grinder pedals" allow the
user to do tricks that involve sliding on the pedals down various
structures such as metal rails. Such pedals may also be formed from
plastic with metal inserts on the bottom surface in order to
decrease wear and friction when sliding.
[0093] As shown in FIGS. 9A and 9B, a bottom bracket assembly,
generally indicated at 700, for receiving a hex shaped slider tube
is illustrated. The bottom bracket assembly 700 includes a bottom
bracket 702 that is sealed with an o-ring 704 to the housing 706
and attached thereto with fasteners 708 and 710. The filter housing
712 is positioned on top of the bracket 702 and the resilient pad
714 is positioned above the filter housing 712. The slider shaft
716 fits within the bushing 718 and is prevented from rotation
therewith. A pair of radially extending, internally threaded bores
720 and 722 are provided for attaching foot support members as
previously described.
[0094] Hydraulic brakes may also be a feature of the pogo stick.
Such brakes allow the user to stop the motion of the slider shaft
by applying a clamping or gripping force to the slider shaft. In
one embodiment, a lever, such as a brake lever found on a
motorcycle is provided on the handlebars. The brakes, which may
include brake pads or engaging members for grasping and holding the
slider shaft, allow the user to prevent the slider shaft from
moving relative to the cylinder such as when, for example, the
slider shaft is not fully extended. The user can stop the motion of
the pogo stick, rest for a moment, and then release the brake
launching the user back into the air.
[0095] The pogo stick of the present invention has significantly
more power than a conventional spring-type pogo stick, is more
maneuverable, allowing the user to perform various tricks, and is
durable and relatively light weight.
[0096] While the apparatus of the present invention has been
described with reference to certain illustrative embodiments to
illustrate what is believed to be the best mode of the invention,
it is contemplated that upon review of the present invention, those
of skill in the art will appreciate that various modifications and
combinations may be made to the present embodiments without
departing from the spirit and scope of the invention as recited in
the claims. For example, the top of the cylinder may be sealed off
with a plastic cap that is attached to or integrally formed with
the top portion of the housing. In addition, while it has been
illustrated that a clamping device is secured to or integrated with
the top cap for holding a pair of handle bars or gripping members
to the top cap, the handle bars could be integrally formed with the
top cap such that the top cap and handle bars are formed from a
single injection molded piece.
[0097] It is also contemplated that a two piece aluminum clamp may
be secured around the handle bars and then attached to the top cap.
Likewise the handle bar clamping mechanism could be formed from
other materials known in the art including polyethylene or
polycarbonate. The claims provided herein are intended to cover
such modifications and combinations and all equivalents thereof.
Reference herein to specific details of the illustrated embodiments
is by way of example and not by way of limitation.
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