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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates in general to skip rope apparata and in
particular to handle and rope construction both as to their structure and
material which permit a less-expensive and more easily utilized
arrangement.
Skip ropes, or alternatively jumping ropes, do not entail an overly
complicated construction. In fact, although the more "polished" designs
utilize handles, small children will play the games of jump or skip rope
using only a length of rope with the free ends of the rope serving as
handles. The most apparent disadvantage with this simplistic construction
is the fact that the rope has a tendency to twist and turn and does not
provide a suitable means for grasping since the rope turns in the hands of
the user. In an effort to overcome the twisting rope problem, various
attempts have been made to construct the handles so that they permit the
rope to turn while the handles remain stationary. Although there may be a
wide variety of ways in which to construct handles which permit the rope
to turn while the handle remains stationary, the criteria of low cost and
ease of construction are important so that such skip ropes would be easily
affordable by all who wish to keep fit by such an exercise technique.
The following listed patents disclose various skip rope handle concepts and
attachment means, and while each of these references may in fact disclose
a construction which at the time of conception was deemed to be novel,
none of the disclosures are believed to be anticipatory of the present
invention in that they do not provide the same type nor convenience of
construction provided by the disclosure of the present invention.
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U.S. Pat. No. Patentee Issue Date
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1,436,703 Fisher 11/28/22
1,508,300 Sacks 9/09/24
1,651,057 Goldstein 11/29/27
2,253,075 Johnson 8/19/41
4,101,123 Anthony 7/18/78
4,179,119 Wolf 12/18/79
4,201,382 Wilson 5/06/80
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Fisher discloses a rope handle construction wherein a wooden turned handle
is arranged with a generally spherical recess into which a ball is placed
such that the ball is larger than the recess opening. The rope for the
skip rope is inserted into the ball and knotted at the back side. Thus,
the rope may turn relative to the ball and the ball may turn relative to
the recess. Consequently, adequate bearing surfaces are provided which
enable the rope to twist while the handles remain stationary. Although the
particular shape, contour and material choice would appear to be a
disadvantage, a more significant drawback of this construction is the fact
that the handle must be fabricated in two sections and then glued or
otherwise secured together. This particular construction concept precludes
the use of conventional piece part shapes and if the skip rope breaks, an
entirely new handle must be constructed.
Sacks discloses a tassle construction and although this reference is
believed to be of only limited relevancy to the present invention, it is
to be noted that a longitudinal passage 11 is provided entirely through
mold 6 and a cord 15 is adapted to be passed through the mold and knotted
as indicated by reference character 16. This particular construction
regarding how the cord is passed through the mold and knotted may have
some relevancy regarding the methods of securing a skip rope to its
corresponding handle.
Goldstein discloses a skip rope construction wherein the end of a contoured
wooden handle is provided with a recessed void into which the rope and a
shouldered bearing sleeve are fitted. The enlarged portion of the
shouldered sleeve rides against the inside surface at the end of the
handle and provides a bearing action for the turning or twisting rope.
This construction thus prevents wear and attempts to reduce the frictional
contact between the rope and the wood handle. Again, the construction of
the wooden handle is quite specialized and the assembly concept does not
permit the user of the skip rope to make that change at the time of
initial purchase. A further drawback would appear to be the degree of
security regarding the clamping of the rope into the recessed void of the
handle since this is accomplished by means of the shouldered bearing
sleeve, any additional force exerted upon the rope would have a tendency
to pull or strip out the rope from the sleeve and thus defeat the entire
construction.
Johnson discloses a skip rope construction wherein the disclosed wooden
handles are completely hollow and include a shouldered or counterbore
portion internally. This counterbore provides a shouldered surface against
which any enlarged attachment to the free end of the rope will ride thus
preventing the rope from pulling out of the handle. What is very
definitely lacking by this construction is any suitable bearing interface
between the turning and twisting rope and the handle. In fact, what occurs
in that as forces are exerted on the rope, the pressure against the
counterbored shoulder becomes greater, thereby increasing the frictional
forces at this interface.
Anthony discloses a jump rope construction which includes a connection
between the rope and a pair of handles which includes a ball bearing
assembly. The ball bearing assembly includes the balls and race which are
disclosed by earlier technology and a housing having an outer flange and
an inner shoulder defining therebetween a handle recess. The construction
still relies on a clamping action around the free end of the rope in order
to provide an enlarged diameter shape which is prevented from pulling
through the inside diameter of the bearing and thus stripping it out of
the handle. As with the prior art references to Goldstein and Johnson, any
arrangement which simply clamps a cylindrical sleeve member or washer
around the rope and then attempts to have that enlarged diameter abut
against a shouldered surface is not as effective as some more positive
retention means. As a skip rope is utilized, there are those times when
tripping on the rope may exert a significant force longitudinally along
the rope, causing the rope to strip out of the handles. Consequently, any
suitable concept for securing the rope to the handles must be very durable
and very positive and it is not believed that these crimping sleeve
constructions are adequate for that intended purpose.
Wolf discloses a skip rope which employs a wire rope in combination with
wooden handles in an arrangement which permits the handles to rotate
freely with respect to the rope. The wooden handles include an axial bore
which has a central section of reduced diameter in which is mounted a
metal peg by means of a bushing supported inside the handle pore. The peg
protrudes from the handle and engages a rope-accommodating part through
which the rope may be looped. While this particular construction may
offset certain earlier disadvantages, its construction is quite
specialized and incorporates a large number of piece parts, all of which
must be properly sized, toleranced and assembled in order to achieve a
working unit.
Wilson discloses a skip rope which includes an elongated flexible element
having first and second end portions and handles attached to the end
portions. Each of the handles includes a tubular hand grip which has a
passage opening at the inner end of the hand grip and a tubular retainer
in the passage opening of the tube. The first end portion of the flexible
element extends through the tube and is attached to a bearing. The bearing
is retained in the passage opening of the hand grip between the outer end
of the retainer and the transverse wall of the hand grip. Again, this
particular construction relies on a ring crimped around the free end of
the rope and which abuts against the face of the bearing. Although a
knotted construction of some sort in disclosed in the FIG. 4 arrangement,
that involves an intermediate component part of the overall apparatus and
is not associated with the handle construction. These intermediate
portions are actually weights and knot 71 is provided to fix the position
of these weights to keep them from shifting longitudinally along the rope.
The corresponding handle construction provides an overly complex system
when it is realized that the primary purpose is simply to allow the rope
to turn and twist independently of the handle.
While each of the above-listed patent references may, in a very crude
sense, provide a means for the skip rope to turn and twist relative to the
handle, none of the construction concepts are believed to be of an
inexpensive, conveniently assembled, highly reliable and durable nature.
However, each of these various advantages are realized by the teachings of
the present invention as will be apparent from the following descriptions.
SUMMARY OF THE INVENTION
A skip rope with handles at each end, each of the handles having a
longituddinal axis and according to one embodiment of the present
invention comprises a hollow, generally cylindrical handlegrip member open
at each end and defining a skip rope-receiving region therethrough and a
pair of shouldered, generally cylindrical bearing members, each bearing
member being arranged with a reduced-diameter plug portion and an
enlarged-diameter head portion and adapted to be received by the
handlegrip member, each of the bearing members defining a through hole
adapted to receive the skip rope.
One object of the present invention is to provide an improved skip rope.
Related objects and advantages of the present invention will be apparent
from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a skip rope according to a typical
embodiment of the present invention.
FIG. 2 is a side elevation view in full section of one handlegrip member of
the FIG. 1 skip rope.
FIG. 3 is a front elevation view in full section of an alternative
handlegrip member also suitable for use as part of the FIG. 1 skip rope.
FIG. 4 is a perspective view of a bearing member comprising a portion of
the FIG. 1 skip rope.
DESCRIPTION OF THE PREFERRED EMBODIMENT
For the purposes of promoting an understanding of the principles of the
invention, reference will now be made to the embodiment illustrated in the
drawings and specific language will be used to describe the same. It will
nevertheless be understood that no limitation of the scope of the
invention is thereby intended, such alterations and further modifications
in the illustrated device, and such further applications of the principles
of the invention as illustrated therein being contemplated as would
normally occur to one skilled in the art to which the invention relates.
Referring to FIG. 1, there is illustrated a skip rope 20 which includes a
length of rope 21, a first handlegrip member 22 at one end and a second
handlegrip member 23 at the opposite end. The length of rope 21 has two
free ends 24 and 25, respectively, and while the length of rope is
permitted to extend through each of the handlegrip members, the rope is
knotted at locations 26 and 27 at the outer end of each corresponding
handlegrip member.
By structuring the clearance aperture through each handlegrip member such
that it is just slightly larger than the outside diameter size of the
length of rope, the existence of knots at locations 26 and 27 prevent the
free ends of the length of rope 24 and 25 from pulling back through the
handles. This particular construction concept is extremely simple and
reliable, and if for any reason the rope becomes worn or breaks, the
handlegrip members are unaffected. All that one must do to install a new
length of rope is to thread the rope through the two corresponding
handlegrip members and knot the rope at the outermost end, the skip rope
is thereafter ready for use.
While there are believed to be a wide variety of handlegrip concepts for a
skip rope, many of which have already been detailed in the background
discussion of the present invention, one criteria and consideration
omitted from all of this prior art is a means to fabricate the handles out
of conventional material shapes and in a manner that provides extremely
low cost yet high reliability and strength. A further consideration
regarding the handle construction is to provide some type of bearing or
lubricated interface between the handlegrip member and the rope so that as
the rope turns and twists, the handlegrip members are unaffected. If such
were not the case, then the rope would abraid more rapidly along the edge
against which it rubs, and it would not provide as smooth of operation for
the user since additional drag would be placed on the rope. Initially,
skip rope handle designs focused on contoured wooden members and fairly
complicated assembly procedures in order to provide some type of bearing
surface. The drawback with these types of designs were of course the
turning operations and contouring required for the handles, most of which
were wooden, and the obvious inability to replace the handles in a
convenient and low-cost fashion. If a wooden handle would break or
otherwise be damaged, it must be completely remade and then reassembled.
Similarly, if the rope would break, many of the handles could not be
reused. However, a possibly more severe drawback with the wooden handle
concepts was the inability to provide a bearing surface between the
interface of the rope and the handle. Designs such as that of the Johnson
Pat. No. 2,253,075 allow the rope to exit directly through an aperture in
the wooden handle and thus the edges of the rope act directly against the
edges of the wooden handle. This is the type of abrasive interface which
is quite undesirable. In order to attempt to overcome this type of
problem, certain earlier designs incorporated ball bearing inserts as part
of the handle mechanism so that there would be greater freedom for the
rope to turn relative to the handle. The drawback with this type of design
is first of all the high cost of inserting bearings in skip rope handles
and secondly, the somewhat involved structural arrangement which is
necessary in order to receive in a properly aligned and secured fashion
the ball bearing inner and outer races.
As an alternative to these somewhat unacceptable prior devices, the present
invention incorporates readily available material shapes which to the
extent necessary may be easily fabricated and very quickly assembled.
Further, if any of the component piece parts become lost or damaged, they
may be easily replaced and assembled. Another important aspect of the
present invention is that the materials selected for the skip rope and the
handlegrip members have a certain self-lubricating relationship to each
other such that there is both less friction and less wear or abrasion at
the interface between the rope and handlegrip members. Although there is
believed to be a variety of handlegrip member arrangements in accord with
the present invention which will satisfy the above objectives, two
illustrations have been provided by FIGS. 2 and 3.
Referring to FIG. 2, one handlegrip member 22 is illustrated in full
section view. Handlegrip member 22 includes a hollow, cylindrical tubular
main body portion 31 and two bearing end plugs 32 and 33. A typical
bearing end plug is illustrated in perspective view in FIG. 4 and includes
a reduced diameter plug portion 34, an enlarged-diameter head portion 35,
and a clearance aperture 36 which is only slightly larger than the outside
diameter of the length of rope. Clearance aperture 36 extends completely
through the corresponding end plug. It is to be understood that the
outside diameter of the plug portion 34 and the inside diameter of main
body portion 31 are nearly equal to each other yet the plug portion is
slightly larger so that when inserted into the main body portion there is
a force or press fit. Due to the fact that the bearing end plugs and the
main body portion are of plastic or synthetic material, several
thousandths of an inch difference in the diameter dimensions can be
accommodated by the force fit without any difficulties. This is due to the
fact that there will be a certain elasticity or give to each of the
component parts and thus, a wider tolerance range is permissible which
would otherwise not be possible with metal or wooden parts. The outside
diameter of the enlarged head portion 35 is nearly equal to the outside
diameter of main body portion 31 so as to provide a generally flush and
cylindrical external appearance to the entire handlegrip member. Also
illustrated in FIG. 2 is a segment of rope 21 as it passes through the
handlegrip member and is knotted at knot location 26 so that the free end
24 cannot be pulled back through the handlegrip member.
Although clearance void 39 which is defined by the cylindrical walls of
main body portion 31 is larger than the clearance aperture 36 through each
of the bearing end plugs, it should be understood that the actual rope and
handle interface is located at clearance aperture 36 and main body portion
31 is not involved directly with any interface with the rope. Although a
force or press fit is deemed more than adequate under the circumstances
and conditions of use, alternative joining techniques are envisioned.
However, it should be pointed out that the force exerted on rope 21 is in
the direction of arrow 40 and thus this force vector actually pulls
bearing end plug 32 into main body portion 31 via the knot at location 26,
thus preventing any loosening of plug 32. Similarly, when the skip rope 20
is in use, the force vector acting on bearing end plug 33 will not
necessarily coincide with the direction of arrow 40. Rather, the force
vector will be more normal to the direction of arrow 40 and actually
causes the length of rope to apply abrasive pressure to the inside
diameter edge 41 of clearance aperture 36. As one uses the skip rope, it
should be apparent from the normal positioning of the handlegrip members
and the movement or travel of the rope that the rope will circle around
diameter edge 41 repeatedly and in fairly rapid succession. For this
reason, it is very important that the materials selected for rope 21 and
the bearing end plugs be compatible to each other such that there is a
somewhat lubricated sliding motion between the two rather than any actual
friction or abrasion. In this regard, there is a variety of material
combinations for the main body portion, the bearing end plugs and the
length of rope which will satisfy the necessary self-lubricating
relationship. Although polypropylene material could be used for all three
component parts of skip rope 20, nylon for all three component parts very
likely provides one of the better self-lubricating arrangements.
Similarly, a main body portion and bearing end plug combination of nylon
with a length of polypropylene rope also is very good as to
self-lubricating properties. One concern or possible drawback with the use
of nylon is its cost and its availability in conventional material shapes.
For this reason, it is believed preferred to select a polyvinylchloride
(PVC) tubing for the main body portion and to use nylon for the bearing
end plugs. Since there is no abrasive interface between the main body
portion and the rope, it is not critical for the main body portion to be
constructed of nylon. Rather, the usage of nylon may be limited to the
bearing end plugs and still achieve the desirable self-lubricating
benefits. It is felt that in this combination a polypropylene rope is
preferred over that of nylon due to its material properties and
characteristics relative to the other parts.
With the foregoing understanding regarding the construction and material
options for the present invention, FIG. 3 discloses an alternative
construction concept for the handlegrip members. Alternative handlegrip
member 45 includes a main body portion 46 and a single bearing end plug
47. Since this illustration is in full section, it should be understood
that main body portion 46 includes a larger clearance aperture 48 to
receive the bearing end plug 47 and a smaller clearance aperture 49 to
receive the length of rope 21. In this particular arrangement, the knotted
portion of the rope may be placed at either end of the alternative
handlegrip member. If the knot is located adjacent the bearing end plug as
illustrated in FIG. 3, then the material for the bearing end plug may be
any one of a variety of synthetic or plastic materials. However, in this
arrangement the main body portion 46 should be constructed of nylon
inasmuch as clearance aperture 49 provides the interface surface between
the main body portion and the length of rope and thus nylon is necessary
in order to provide the good self-lubricating properties between these two
materials. The length of rope should be constructed of polypropylene as
has been previously described. On the other hand, if the knotted portion
of the length of rope is disposed adjacent the opposite end near clearance
aperture 49, then the main body portion may be constructed of PVC tubing
or a similar synthetic material and the bearing end plug is constructed of
nylon.
While the invention has been illustrated and described in detail in the
drawings and foregoing description, the same is to be considered as
illustrative and not restrictive in character, it being understood that
only the preferred embodiment has been shown and described and that all
changes and modifications that come within the spirit of the invention are
desired to be protected.
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