U.S. patent number RE31,113 [Application Number 06/112,888] was granted by the patent office on 1982-12-28 for variable resistance lifting mechanism.
Invention is credited to Charles M. Coker, Gary M. Kling.
United States Patent |
RE31,113 |
Coker , et al. |
December 28, 1982 |
**Please see images for:
( Certificate of Correction ) ** |
Variable resistance lifting mechanism
Abstract
A variable resistance lifting mechanism for increasing the
resistive force during an exercise stroke includes a lever arm
pivotally attached to a frame at one end and slidably mounted
through a linear bearing sleeve at a position remote from the pivot
point. In one embodiment, the linear bearing sleeve is connected by
a clevis pin to a housing slidable in a linear manner on guide
bars. A bar secured to the housing is adapted to be attached to a
predetermined number of weights. The weights are also slidable in a
linear manner on the guide bars. In a second embodiment, the linear
bearing sleeve is pivotally connected by the clevis pin directly to
the bar adapted to the attached to the predetermined number of
weights. Pivoting of the lever arm by the user causes pivoting of
the sleeve with the lever arm about the remote pivot point and
simultaneous linear movement of the sleeve and the attached weights
so that the lifting force is distributed over a length of the lever
arm and the bending force is distributed over a length of the guide
bars.
Inventors: |
Coker; Charles M. (Huntington
Beach, CA), Kling; Gary M. (Fullerton, CA) |
Family
ID: |
26810464 |
Appl.
No.: |
06/112,888 |
Filed: |
January 17, 1980 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
767412 |
Feb 10, 1977 |
04093213 |
Jun 6, 1978 |
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Current U.S.
Class: |
482/98 |
Current CPC
Class: |
A63B
21/0615 (20130101); A63B 21/4047 (20151001); A63B
21/0617 (20151001); A63B 21/063 (20151001) |
Current International
Class: |
A63B
21/06 (20060101); A63B 21/062 (20060101); A63B
021/06 () |
Field of
Search: |
;272/118,117,143,144,134,135,136 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Pinkham; Richard C.
Assistant Examiner: Browne; William R.
Attorney, Agent or Firm: Nilsson, Robbins, Dalgarn,
Berliner, Carson & Wurst
Claims
What is claimed is: .[.1. A variable resistance lifting mechanism,
comprising:
a frame having means for guiding the movement of weights:
1ever arm means pivotally attached to said frame at a pivot point
and constructed to permit substantially only reciprocation of said
lever arm means with respect through a sleeve means when said lever
arm means as pivoted by a user
a pivotable, linear bearing sleeve means for receiving said lever
arm means in telescoping relationship, said sleeve means being
mounted at a position remote from said lever arm means pivot point,
said sleeve means being mounted for linear movement within said
guide means and for simultaneous pivotal with respect to said frame
to maintain alignment with said lever arm, said sleeve means
simultaneously distributing a user's lifting forces over a
substantial length of the respective lever arm means during lifting
of the lever arm means
bar weight supporting means pivotally connected to said each linear
bearing sleeve means;
a plurality of weights slidably mounted for linear movement of said
guide means, said weight having adapted to distribute the forces
against said guide means over a length of said guide means;
and,
means for attaching a selected number of said weights to said bar
means,
whereby pivoting by a user of said lever arm means about its pivot
point causes pivoting said linear bearing sleeve means with respect
to said guide means and simultaneous linear movement of said sleeve
means and of said weights on said guide means..]. .[.2. The
mechanism as defined in claim 1, further comprising a housing
slidably mounted on said guide means and adapted to connect said
linear bearing sleeve to said bar means, said housing providing
further simultaneous distribution of the bending forces over a
longitudinal length of said guide means as said weights and
housing
are moved linearly on said guide means..]. 3. .[.The mechanism as
defined in claim 2, further comprising.]. .Iadd.A variable
resistance lifting mechanism, comprising:
a frame having means for guiding the movement of weights;
1ever arm means pivotally attached to said frame at a pivot point
and constructed to permit substantially only reciprocation of said
lever arm means through a sleeve means when said lever arm means is
pivoted by a user;
a pivotable, linear bearing sleeve means for receiving said lever
arm means in telescoping relationship, said sleeve means being
mounted at a position remote from said lever arm means pivot point,
said sleeve means being mounted for linear movement within said
guide means and for simultaneous pivotal movement with respect to
said frame to maintain alignment with said lever arm, said sleeve
means simultaneously distributing a user's lifting forces over a
substantial length of the lever arm means during lifting of the
lever arm means;
bar weight supporting means pivotally connected to said linear
bearing sleeve means;
a plurality of weights slidably mounted for linear movement on said
guide means, said weight being adapted to distribute the forces
against said guide means over a length of said guide means;
means for attaching a selected number of said weights to said bar
means,
whereby pivoting by a user of said lever arm means about its pivot
point causes pivoting of said linear bearing sleeve means with
respect to said guide means and simultaneous linear movement of
said sleeve means and of said weights on said guide means;
a housing slidably mounted on said guide means and adapted to
connect said linear bearing sleeve to said bar means, said housing
providing further simultaneous distribution of the bending forces
over a longitudinal length of said guide means as said weights and
housing are moved linearly on said guide means; and .Iaddend.a
clevis pin pivotally connecting said linear
bearing sleeve means to said housing. 4. .[.The mechanism as
defined in claim 1, further comprising.]. .Iadd.A variable
resistance lifting mechanism, comprising:
a frame having means for guiding the movement of weights;
1ever arm means pivotally attached to said frame at a pivot point
and constructed to permit substantially only reciprocation of said
lever arm means through a sleeve means when said lever arm means is
pivoted by a user;
a pivotable, linear bearing sleeve means for receiving said lever
arm means in telescoping relationship, said sleeve means being
mounted at a position remote from said lever arm means pivot point,
said sleeve means being mounted for linear movement within said
guide means and for simultaneous pivotal movement with respect to
said frame to maintain alignment with said lever arm, said sleeve
means simultaneously distributing a user's lifting forces over a
substantial length of the lever arm means during lifting of the
lever arm means;
bar weight supporting means pivotally connected to said linear
bearing sleeve means;
a plurality of weights slidably mounted for linear movement on said
guide means, said weight being adapted to distribute the forces
against said guide means over a length of said guide means;
means for attaching a selected number of said weights to said bar
means,
whereby pivoting by a user of said lever arm means about its pivot
point causes pivoting of said linear bearing sleeve means with
respect to said guide means and simultaneous linear movement of
said sleeve means and of said weights on said guide means; and
.Iaddend.a clevis pin pivotally connecting said linear bearing
sleeve means to said bar means. .[.5. A variable resistance lifting
mechanism as defined in claim 1 wherein said bar means includes a
plurality of pin receiving holes and said bar means passes through
apertures in each of said weights, said means for attaching
comprising a pin connecting a selected number of said weights to
said bar means, whereby said weights simultaneously distribute the
lifting forces against said guide means over a longitudinal length
of said guide means..].
Description
BACKGROUND OF THE INVENTION
The present invention is directed to a variable resistance lifting
mechanism and, more particularly, to a mechanism for a machine
which provides the proper increased resistance during an exercise
stroke to maintain maximum muscular effort throughout the range of
movement of the user.
There are natural changes which occur in the human lever system
while performing movements that necessitate different levels of
muscular involvement. The variation in muscular force or
involvement results from the biomechanical advantages and
disadvantages of the human lever system. When the human lever is in
the position of greatest biomechanical disadvantage, maximum
muscular involvement is required. When the human lever system is at
its greatest advantage, minimum muscular force is required.
In order to provide the desired constant maximum muscular
involvement throughout an exercise stroke, it is necessary to vary
the resistance so that when the human lever is in a position of
greatest biomechanical disadvantage, the resistance is at a
minimum. Correspondingly, the resistance should be increased as the
biomechanical advantage of the human lever system increases. Thus,
by properly varying the resistance of the exercise machine during
the exercise stroke, it is possible to maintain the same degree of
muscular involvement throughout the entire exercise stroke.
Various prior art devices have sought to provide variable
resistance during an exercise stroke. The most widely used prior
art device includes a cam wheel pivotally mounted to the frame of
an exercise machine. This device includes a chain secured
tangentially to the cam wheel at one end, wrapped around a roller,
and having weights secured to the opposite end of the chain. A
lever arm is connected to the cam wheel and a user exerts force
against the lever arm to rotate the cam. As the came rotates, the
distance from the cam pivot point to the point on the cam surface
from which the chain extends tangentially increases. This increases
the moment arm of the cam wheel and correspondingly increases the
force a user must exert against the lever arm to rotate the cam
wheel.
Such cam wheel devices are extremely heavy and require numerous
mechanical components which create excessively high moments of
inertia. This adverse inertia force becomes the dominant driving
force, particularly when the exercise stroke is performed at a
rapid speed, and therefore effectively distorts the pattern of
increased resistance and effectively prevents constant maximum
muscular involvement during the exercise stroke.
In order to avoid the inertia problem of cam wheel devices, a
second type of prior art variable resistance exercise device was
designed which includes a lever arm pivotally attached to a frame
having guide bars. Three rollers are secured to a U-shaped member
with two guide rollers adapted to roll directly on the vertical
guide bars. The third main roller is adapted to roll on the upper
surface of the lever arm passing beneath the third roller and
through the U-shaped member. The U-shaped member is rigidly
connected to a selector bar which is in turn adapted to be attached
to weights which slide on the guide bars. In the operation of such
a device, as the user exerts force against the lever arm during the
exercise stroke, the lever arm exerts force against the third main
roller to lift the U-shaped member and the attached weights. The
two guide rollers roll vertically upward on the guide bars to
provide linear movement of the weights.
This prior art roller mechanism has two primary disadvantages. The
first disadvantage is the tendency of the rollers to wear, thus
increasing friction and requiring constant maintenance. The wearing
of the two guide rollers prevents them from providing a relatively
frictionless surface against the vertical guide bars. The wearing
of the third main roller distorts the relatively frictionless
surface against the lever arm.
The second disadvantage of the prior art roller mechanism is its
creation of adverse bending moments against the vertical guide
bars. The two guide rollers cause a localized tangential force
against the guide bars at the point of contact the guide rollers
with the guide bars which eventually tends to bend the guide bars.
Furthermore, the tangential force of the third main roller against
the lever arm causes a localized bending force on the lever arm.
These bending forces distort the pattern of increased resistance
during the exercise stroke thus destroying the object of the device
which is to maintain constant maximum muscular involvement
throughout the exercise stroke.
SUMMARY OF THE INVENTION
The present invention is directed to a variable resistance lifting
mechanism having a frame and guide means. A lever arm is pivotally
attached to the frame and is slidably mounted in a linear bearing
sleeve at a position remote from the pivot point. The sleeve is
pivotally mounted for linear movement within the guide means. Bar
means are pivotally connected to the linear bearing sleeve. A
plurality of weights are slidably mounted on the guide means and
means are provided for attaching a selected number of weights to
the bar means. Rotation of the lever arm by the user causes
rotation of the linear bearing sleeve with the lever arm about the
remote pivot point, and further causes linear movement of the
sleeve and of a selected number of weights on the guide means.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings which constitute part of this specification,
exemplary embodiments demonstrating various features of this
invention are set forth wherein:
FIG. 1 is a cross-sectional, elevational view of a first embodiment
of the invention at the beginning of an exercise stroke;
FIG. 2 is a cross-sectional, elevational view of the embodiment of
the invention shown in FIG. 1 at the end of an exercise stroke;
FIG. 3 is a cross-sectional, elevational view of various details of
the first embodiment of the invention shown in FIG. 1;
FIG. 4 is a cross-sectional, elevational view taken along the line
4--4 of FIG. 3;
FIG. 5 is a cross-sectional elevational view of various details of
a second embodiment of the invention wherein the sleeve is directly
connected to the selector bar; and,
FIG. 6 is a cross-sectional, elevational view taken along the line
6--6 of FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention provides a variable resistance lifting
mechanism for maintaining the proper resistance during an exercise
stroke by eliminating or distributing undesirable forces. The
machine includes a lever arm 12, which is pivotally attached to a
frame 10 of the machine, and is slidaby mounted in a rotatable,
linear bearing sleeve 16 at a position remote from the lever arm
pivot point 14. The lever arm 12 is operatively connected to a
selector bar 24 which is adapted to be secured to a predetermined
number of weights 28. The weights 28 are slidably mounted on guide
rails 20 and 22 of the frame.
The sleeve 16 is adapted to distribute the lifting forces exerted
by a user over a substantial length of the lever arm 12. The
weights 28 are adapted to distribute bending forces over a
substantial length of the guide rails. These features of the
invention substantially reduce the bending of the lever arm and
guide rails which is caused by the rollers of the prior art
devices. The present invention thus prevents or reduces distortion
of the pattern of variable resistance caused by roller-type prior
art devices.
In the first embodiment of the invention, the sleeve 16 is
pivotally connected to a housing 18 which is slidably mounted on
the guide rails. The housing 18 further provides distribution of
bending forces over the guide rails to further reduce the bending
effect caused by the roller-type prior art devices. For this latter
purpose, the housing top and bottom plates function as do the
weight in the second embodiment to be described herein.
As shown in FIGS. 1 and 2, the variable resistance lifting
mechanism of the present invention includes a frame 10 having a
lever arm 12 attached to the frame at a pivot point 14. The lever
arm is slidably mounted in a rotatable linear bearing sleeve 16 at
a point remote from the pivot 14. The distance from the pivot point
14 to the sleeve 16 along the arm 2 is at a minimum at the
beginning of the exercise stroke, as shown in FIG. 1, and the
distance increases to a maximum at the end of the exercise stroke,
as shown in FIG. 2. The device is thus constructed to provide
variation in resistance from the beginning of the exercise stroke
to the end of the exercise stroke in accordance with biomechanial
research known in the art. This provides a constant maximum
muscular force throughout the exercise stroke.
In the first embodiment of the invention, shown in FIGS. 1-4, the
housing 18 is slidably mounted on guide bars or rails 20 and 22 as
is shown in greater detail in FIGS. 3 and 4. The housing 18 has top
and bottom plates, each about 1.5 inches thick, and a selector bar
24 attached to the lower or bottom plate by a roll pin 25. A
plurality of weights 28, each about 1.5 inches thick, are slidably
mounted on the guide bars 20 and 22 and a selector pin 26 is
adapted to attach a selected number of the weights 28 to the
selector bar 24, as is shown in FIG. 4.
The sleeve 16 incorporates suitable low friction annular bearings
38, which are formed of nylon, Teflon, or the like. The sleeve 16
is four inches in length and the two bearings 38 are each one inch
in length. The sleeve 16 has integral ears 34 and 36 which have
horizontal bores through which a clevis pin 30 is fitted. The
clevis pin 30 also passes through a horizontal bore in the housing
arm 32 to pivotally secure the sleeve 16 to the housing 18. The
clevis pin 30, as shown in FIG. 3, extends slightly beyond both
ears 34 and 36, and the ears 34 and 36 have a slight tolerance
between their respective inner surfaces and the housing arm 32. In
this manner, the clevis pin permits a limited amount of lateral
movement of the sleeve 16 with respect to the rear pivot point 14
to accommodate a slight lateral movement of the lever arm 12 at the
pivot point 14 which would otherwise cause bending of the clevis
pin 30. This construction of the clevis pin 30 permits lateral
movement of the linear bearing sleeve with respect to the pivot
point 14 to maintain alignment of the lever arm 12 between the
sleeve 16 and the pivot point 14. Maintaining this alignment of the
lever arm 12 prevents bending of the clevis pin 30.
In operation of the first embodiment of the invention shown in
FIGS. 1-4, the lever arm 12 is initially in the position shown in
FIG. 1. The selector pin 26 is inserted through the horizontal bore
of a weight and a corresponding horizontal bore of the selector bar
24. As the user lifts the lever arm 12, the sleeve 16 and the
housing 18 are raised and the sleeve 16 rotates with the lever arm
about the pivot point 14 to the position shown in FIG. 2. At the
same time, the selected number of weights are lifted linearly
upward on the guide bars 20 and 22 by the selector pin 26 and
selector bar 24 attached to the housing 18. Since the length of the
lever arm between the pivot point 14 and the sleeve 16 is increased
during the stroke, the lifting force required to be exerted against
the end of the arm 12 remote from the pivot 14 increases during the
stroke to thereby provide a variable resistance during the exercise
stroke.
The sleeve 16 is adapted to distribute the lifting force over a
length of the lever arm 12 throughout the exercise stroke to
thereby substantially reduce the bending forces applied
tangentially against the lever arm 12 by the prior art roller-type
devices. In addition, the weights 28 which move linearly on the
guide bars 20 and 22 further distribute the forces over the guide
bars 20 and 22. This substantially reduces the local bending forces
against the guide bars 20 and 22 caused by rollers used in prior
art devices. Finally the housing 18 further distributes the bending
forces against the guide bars when the weights are moved linearly
on the guide bars.
In the second embodiment of this invention, shown in FIGS. 5 and 6,
a linear bearing sleeve 40 slidably surrounds lever arm 41. The
sleeve 40, incorporating bearings 43 as previously described, is
pivotally connected by a clevis pin 42 to a selector bar 48. The
sleeve 40 includes ears 44 and 46 having horizontal bores to
receive the clevis pin 42. The clevis pin 42 is fitted through the
bores in the ears and through a horizontal bore in the selector bar
48 to provide a pivotal connection. A selector pin 50 is provided
to attach a desired number of weights 52 to the bar 48 as
previously described. The weights 52 are slidably mounted on guide
bars 54 and 56. When a user rotates the lever arm 41, the linear
bearing sleeve 40 moves linearly between the guide bars and is
rotated about the remote lever arm pivot point. Simultaneously, the
selected number of weights 52 are moved linearly on guide bars 54
and 56.
The second embodiment of the invention shown in FIGS. 5 and 6
eliminates the housing 18 of the first embodiment, shown in FIGS. 1
through 4, while providing the same benefits of distributing the
lifting forces over a length of the lever arm 41 as well as
distributing the bending forces against the guide bars 52 and 54 to
thereby substantially reduce the bending of the lever arm and the
guide bars. This reduces the distortion of the desired pattern of
variable resistance over the exercise stroke.
It will be apparent that various modifications and changes may be
made in the disclosed embodiments, all within the scope of the
invention as defined by the following claims.
* * * * *