U.S. patent application number 12/906841 was filed with the patent office on 2012-04-19 for barbell having decreased destabilizing forces and method for making same.
This patent application is currently assigned to Grace Premier Fitness And Wellness Products, inc.. Invention is credited to Karl Anderson.
Application Number | 20120094810 12/906841 |
Document ID | / |
Family ID | 45934634 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120094810 |
Kind Code |
A1 |
Anderson; Karl |
April 19, 2012 |
Barbell Having Decreased Destabilizing Forces And Method For Making
Same
Abstract
A adjustable barbell producing decreased destabilizing forces
during the lifting movement, and a method for making same, includes
a bar having a pair of longitudinally-separated inner collars
weighing no less than approximately 30 lbs, a pair of sleeves
mounted for rotation about the longitudinal axis of the bar and
sized to accommodate the through-holes of removable weight plates
mounted on said sleeves, each sleeve being positioned
longitudinally outward of a respective one of said collars, the
collars thereby decreasing the stress on the bar and the moment of
inertia of the weight being lifted.
Inventors: |
Anderson; Karl; (Glendora,
CA) |
Assignee: |
Grace Premier Fitness And Wellness
Products, inc.
Vancouver
WA
Ace Specialty, Inc.
Rosemead
CA
|
Family ID: |
45934634 |
Appl. No.: |
12/906841 |
Filed: |
October 18, 2010 |
Current U.S.
Class: |
482/107 |
Current CPC
Class: |
A63B 21/0724 20130101;
A63B 21/063 20151001; A63B 21/0728 20130101; A63B 21/075 20130101;
A63B 2209/00 20130101; A63B 21/4035 20151001 |
Class at
Publication: |
482/107 |
International
Class: |
A63B 21/075 20060101
A63B021/075 |
Claims
1. A method for decreasing the destabilizing forces acting on an
adjustable barbell during a weightlifting movement comprising the
steps of: affixing a pair of longitudinally separated collars
weighing at least approximately 40 pounds each to a generally
longitudinally-extending bar, the collars being positioned to
permit the removable mounting of weight plates longitudinally
outward of the collars by a user of the barbell.
2. A method for assembling an adjustable barbell generating
decreased destabilizing forces during a weightlifting movement
comprising the steps of: affixing a pair of longitudinally
separated collars weighing of at least approximately 40 pounds each
to a generally longitudinally-extending bar to reduce the momentum
of inertia resulting from weight being lifted; mounting a pair of
sleeves for rotation about the generally longitudinal axis of said
bar, said sleeves being sized to accommodate generally central
through-holes of removable weight plates mounted on said sleeves,
each sleeve being positioned longitudinally outward of a respective
collar.
3. An adjustable barbell for lifting a desired amount of weight and
comprising: a generally longitudinally-extending bar extending
along a first generally longitudinal axis between a pair of end
regions; a pair of longitudinally separated collars weighing at
least approximately 40 pounds each and affixed to the bar; a pair
of sleeves mounted at respective end regions of the bar for
rotation about a second generally longitudinal axis, said sleeves
being sized to accommodate generally central through-holes of
removable weight plates mounted on said sleeves, each sleeve being
positioned longitudinally outward of a respective one collar.
4. The barbell of claim 3 wherein the first and second axes are
generally coaxial.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field Of The Invention
[0002] This invention relates to barbells.
[0003] 2. Background Art
[0004] A barbell is a piece of exercise equipment used in weight
training, weightlifting and power lifting. Barbells typically have
a generally longitudinally-extending bar that is between 4 feet
(1.2 m) and 7 feet (2.1 m) long, with a diameter of approximately
one inch (2.54 cm). The bar is often engraved in its central region
with a knurled pattern where it is to be gripped by the user.
[0005] There are two fundamental types of barbells: the "fixed
weight" type, wherein the weight plates are permanently secured on
the ends of a bar, and the "adjustable" type, wherein weight plates
at each end region are secured on the bar between a inner affixed
collar and an outer removable collar to permit the user to add or
remove individual weight plates to the bar. This invention pertains
to adjustable barbells.
[0006] Adjustable barbells comprise a generally
longitudinally-extending bar. Weights plates are slid onto the
longitudinally outer end regions of the bar to obtain the desired
total weight to be lifted, and are secured between a longitudinally
inner collar affixed to each end region of the barbell and a
removable longitudinally outer collar that is removable by the user
when the addition or removal of weight plates is desired. The
collars prevent the weight plates from sliding off of, or along,
the bar and from wobbling during the exercise movement. In addition
to preventing injury and/or property damage from a falling weight
plate, the collars are intended to prevent the destabilizing
effects on the barbell of sliding, falling and wobbling weight
plates, which can cause muscular and skeletal injuries.
[0007] One type of adjustable barbell is the Olympic barbell, and
is used by "serious" weightlifters. While conventional fixed
barbells are typically limited to about 250 lbs of weight, Olympic
barbells can accommodate 600 lbs or more and are frequently used to
lift poundage well in excess of 350 lbs to as much as 1000 lbs. The
Olympic bar used by men has defined standard dimensions. It is a
metal bar that is 2.2 m (7.22 ft) long. The outer ends are 50 mm
(1.9685 inches) in diameter. The central grip section of the bar is
28 mm (1.1024 inches) in diameter. The spacing between the inner
collars is 1.34 meters (52.675 inches). The Olympic bar used by
women is shorter (2.05 m) with a thinner grip section (25 mm).
[0008] Olympic barbells typically include a tubular sleeve coupled
to the bar at each end region onto which the weight plates are
mounted. The sleeve is mounted on bushings or bearings about the
bar for rotation, permitting the weight plates to rotate about the
longitudinal axis of the bar during the exercise movement. This
reduces destabilizing torque that the plates can transmit to the
bar owing to the rotationally-directed inertia of the weight plate
that opposes plate acceleration and deceleration during the
exercise movement. Given the tremendous forces created by the huge
poundage being lifted, there is great concern about (and attention
paid to) the injurious effects of the consequential and substantial
destabilizing forces that are generated during the exercise
movements.
SUMMARY OF THE INVENTION
[0009] To reduce the destabilizing forces generated on the bar by
the weight plates, the inner collar associated with the barbell is
increased in weight. Because the inner collar is relatively close
to the user's hand during the movement, the moment arm associated
with the weight is substantially less than the moment arm that
would be associated with an equal weight at a relatively
longitudinally-outer position. The decreased moment arm reduces the
destabilizing force attributable to that weight, resulting in a
more controllable barbell at a given poundage.
[0010] I believe that the destabilizing forces are reduced because
of the lesser moment of inertia ("MOI") attributable to the
resulting configuration. MOI is the resistance of the weight plate
mass to changes in velocity. These changes occur, for example, when
the barbell is first lifted, causing the weight plates to
accelerate from a zero velocity. During the movement, slight
changes in velocity occur owing to the characteristics of the
lifter's muscular-skeletal construction, which results in uneven
acceleration of the barbell over the course of movement, together
with a generally arcuate path of motion of the plates (which can be
thought of as concurrent changes in velocity in the horizontal and
vertical directions). The bar experiences a bending downward as the
plates are accelerated at the commencement of the movement. As the
barbell reaches the end of the movement, the barbell approaches
zero velocity, but the inertia of the weight plates causes them to
resist deceleration, resulting in a bending of the bar upward. In
addition, the lifter likely has a dominant side--be it left or
right--that results in uneven forces being applied to the left and
right sides of the barbell. All of this creates a complex
combination of destabilizing forces that can make the bar difficult
to control.
[0011] The MOI associated with a given mass increases with the
square of its distance from the axis of rotation. Thus, a weight
plate at the end of the bar has significantly more MOI than the
same weight plate near the mass' center of rotation during the
lifting movement. The stress imposed on the bar by a weight plate
increases linearly with its distance from the fulcrum. Accordingly,
destabilizing forces and bar stresses are reduced when the inner
collars associated with the barbell are increased in weight in lieu
of the same weight being positioned at the longitudinally-outmost
positions.
[0012] Preferably, the weight of the innermost collar is increased
beyond conventional collars sufficiently so that the bar and inner
collars weigh a total of approximately 80 lbs or more.
[0013] These and further details of the invention will be apparent
to those of ordinary skill in the art from reading a description of
the preferred embodiment of the invention described below, of which
the drawing forms a part.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0014] FIG. 1 is a front perspective view of a barbell constructed
in accordance with the invention;
[0015] FIG. 2 is a front perspective view of the barbell of FIG. 1
behind a conventional barbell; and
[0016] FIG. 3 is a front perspective view of the barbell of FIG. 1
with weight plates mounted thereon.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Referring to FIGS. 1 and 2, a barbell 10 comprises a
generally cylindrical bar 12 extending along a longitudinal axis
11, and having a pair of longitudinally-spaced apart inner collars
14, 16. The bar has a central region 18 defined between the inner
collars, and longitudinally outer end regions 18, 20 extending
longitudinally outward from the inner collars to the ends 22, 24 of
the bar.
[0018] A pair of cylindrical sleeves 26, 28 are mounted at the
longitudinally outer end regions 18, 20 respectively for rotation
about the axis 11, and are sized to accommodate the generally
central through-holes of weight plates mounted about the sleeves.
Bearings or bushings are utilized between the sleeves and bar to
permit the rotation, and many exemplary configurations of bushings
and bearings are known in the art.
[0019] Those skilled in the art will recognize that the sleeves may
be mounted for rotation about a longitudinal axis that is not
coaxial with the longitudinal axis that passes through the major
portion of the bar that lies between the collars. This
configuration permits the plates' centers of mass to be positioned
below that portion of the bar's axis that passes through the region
where the user grips the bar. Accordingly, the invention herein is
not limited to the axis of the bar and the axis of the sleeves
being wholly coaxial.
[0020] The inner collars 14, 16 weigh at least 20 lbs each,
preferably at least 40 lbs each, and are affixed to the bar 10.
Preferably, the collars are interference-fit onto the bar and are
welded in place. FIG. 2 illustrates the preferred collars 14, 16 of
the invention vis-a-vis conventional collars 140, 160 of a prior
art dumbbell 100.
[0021] FIG. 3 illustrates the barbell of FIG. 1 with weight plates
30 mounted thereon. The weight plates are not affixed to the
barbell, but are removable and replaceable by the user to obtain
desired poundage. When the desired weight plates have been loaded
onto the bar, the weight plates are secured on the bar with a
removable collars (not shown) that securely captures the weight
plates between the removable collar and the inner fixed collar 14,
16. Conventionally, the weight plates do not exceed 45 lbs. apiece
or so, to enable the user to safely load and remove them from the
barbell.
[0022] Because the preferred collars 14, 16 can be increased to any
desired weight above 40 lbs each, the barbell can accommodate
virtually any anticipated liftable poundage while minimizing
destabilizing forces associated with the weight plates' moments of
inertia and also permitting heavy poundage to be lifted without a
need to employ longer bars. It may be noted, in this regard, that
the moments of inertia associated with weight plates positioned
near the ends of a bar in excess of the seven foot standard length
are greatly increased because the MOI increases with the square of
the plates' distances from the axis of rotation. Accordingly, the
ability to retain a 7 foot length is significant when destabilizing
forces are of concern.
[0023] In addition to the foregoing improvements, a barbell
constructed in accordance with the invention subjects the bar to
less stress for a given liftable poundage. When weight plates are
loaded onto a bar, and supported above ground level by the bar, the
outer ends regions of the bar tend to bow downward below the bar's
center region. The degree of bowing caused by a given weight plate
increases as its distance from the center of the bar increases
because the force acting on the bar is a product of the weight and
its distance from the bar's center (i.e., the fulcrum of the
resulting lever). The bowing of the bar arising from the poundages
lifted by serious weight lifters adds another degree of instability
to the lifting movement as the bar flexes up and down owing to the
intertia of the weight plates and their respective moment arms.
Those of ordinary skill in the art recognize that this instability
results in a further lack of controlled lifting, with a
consequential risk of injury and/or property damage. Moreover,
flexing can, over time, cause metal fatigue in the bar, leading to
additional risk of injury and/or damage.
[0024] A barbell constructed in accordance with the invention
reduces the degree of bowing for a given poundage by reducing the
moment arm over which the weigh plates act, while providing a
barbell that conforms to the bar dimensions and collar separation
imposed by the Olympic bar standards.
[0025] One example of a barbell constructed in accordance with the
invention comprises a pair of 50 lb. steel collars 14, 16 having a
10 inch diameter and a 2.375 inch thickness. The end portion 18, 20
of the bar (and its overlying rotatable sleeve 26, 28) are
approximately 15.375 inches in length, the sleeve diameter being
approximately 1.97 inches. Another example of a barbell constructed
in accordance with the invention comprises a pair of 100 lb. steel
collars 14, 16 having a 14 inch diameter, while a third example
comprises a pair of 150 lb. steel collars 14, 16 having a 17 inch
diameter, the remaining dimensions of the barbell preferably
remaining the same as the first example in both cases.
[0026] Those skilled in the art having the benefit of this
disclosure will recognize that the various dimensions, materials
and weights of the collars can be utilized to achieve the described
improvement; all such modifications are within the spirit and scope
of the invention. Although the present invention and its advantages
have been described in detail, it should be understood that various
changes, substitutions and alterations can be made herein without
departing from the spirit and scope of the invention as will be
defined by appended claims.
* * * * *