U.S. patent application number 11/479108 was filed with the patent office on 2008-01-03 for exercise machine.
Invention is credited to Joel P. Husted, Royce H. Husted.
Application Number | 20080004163 11/479108 |
Document ID | / |
Family ID | 38877414 |
Filed Date | 2008-01-03 |
United States Patent
Application |
20080004163 |
Kind Code |
A1 |
Husted; Royce H. ; et
al. |
January 3, 2008 |
Exercise machine
Abstract
An exercise machine for providing a motion, climbing a hill with
hand weights, includes single swing arms with fixed foot platforms
and forwardly extending substantially horizontal handles. The swing
arms and foot platforms are interlocked through a flexible link and
pulley arrangement. The machine has provision for adjusting the
length of the travel arcs, which changes length of stride of the
foot platforms, and the climbing effect, which alters the workout
intensity. The machine of the invention is readily foldable for
storage.
Inventors: |
Husted; Royce H.; (Forest,
VA) ; Husted; Joel P.; (Forest, VA) |
Correspondence
Address: |
Nicholas A. Camasto Ltd.
545 Thatcher
River Forest
IL
60305
US
|
Family ID: |
38877414 |
Appl. No.: |
11/479108 |
Filed: |
June 30, 2006 |
Current U.S.
Class: |
482/57 ;
482/112 |
Current CPC
Class: |
A63B 22/0056 20130101;
A63B 2022/0051 20130101 |
Class at
Publication: |
482/57 ;
482/112 |
International
Class: |
A63B 22/06 20060101
A63B022/06 |
Claims
1. An exercise machine comprising: a frame supporting vertically
elevated and horizontally displaced pivots, a vertical plane
through the horizontal axis of said pivots defining a zero
position; a pair of single swing arms, each including a foot
platform rigidly secured thereto, rotatably coupled to respective
ones of said pivots; said single swing arms being interconnected to
cause alternating movement of said foot platforms through a
coincident position defined by said foot platforms being alongside
each other; and a bias system for biasing said swing arms such that
said coincident position is in front of said zero position.
2. The machine of claim 1, further including a pair of handles,
each movable with a respective one of said swing arms, which extend
substantially horizontally beyond said coincident position.
3. The machine of claim 1, wherein said bias system includes: a
pulley arrangement coupled to said frame in front of said
coincident position; and a flexible link traversing said pulley
arrangement and engaging said foot platforms.
4. The machine of claim 3 wherein the length of said flexible link
is adjustable.
5. The machine of claim 4, further including an adjustment
mechanism for enabling a user to change the effective length of
said flexible link.
6. The machine of claim 5, wherein said adjustment mechanism
includes: a movable pin on one end of said flexible link; and a
plurality of apertures, located adjacent a corresponding swing arm,
engageable with said pin.
7. The machine of claim 6, further including a pair of handles, at
substantially the level of said pivots, said handles being movable
with a respective one of said swing arms and extending
substantially horizontally beyond said coincident position.
8. The machine of claim 3, wherein the distance between said pulley
arrangement and said coincident position is adjustable.
9. The machine of claim 3, wherein: said pulley arrangement is
rotatably mounted on said frame below said arcs; and said flexible
link engages the heels of said foot platforms, whereby said arcs
may substantially overlap said pulley arrangement.
10. The machine of claim 9, wherein said frame includes: front and
rear supports hinged to form an "A" configuration; and a pair of
flexible tension braces connecting said front and rear
supports.
11. The machine of claim 3, wherein said bias system is adjustable
for changing the distance between said zero position and said
coincident position.
12. The machine of claim 3, wherein said bias system is adjustable
for changing the length of said arcs.
13. The machine of claim 3, wherein said bias system is adjustable
for independently changing the distance between said zero position
and said zero position and changing the length of said arcs.
14. The machine of claim 13, wherein said bias system is adjustable
for simultaneously changing the distance between said zero position
and said coincident position and the length of said arcs.
15. An exercise machine comprising: a frame supporting vertically
elevated and horizontally displaced pivots, a vertical plane
through the horizontal axis of said pivots defining a zero
position; a pair of single swing arms, each including a foot
platform rigidly secured thereto, coupled to respective ones of
said pivots; said single swing arms being interconnected to cause
alternating movement of said foot platforms in arcs through a
coincident position defined by said foot platforms being alongside
each other; a bias system, for biasing said swing arms such that
said coincident position is in front of said zero position, said
bias system including: a pulley arrangement mounted on said frame
below said arcs in front of said coincident position; a flexible
link traversing said pulley arrangement and engaging said foot
platforms; and said flexible link engaging the heels of said foot
platforms, whereby said arcs may substantially overlap said pulley
arrangement.
16. The machine of claim 15, wherein said frame includes: front and
rear supports hinged together to form an "A" configuration; and a
pair of flexible tension braces connecting said front and rear
supports.
17. An exercise machine comprising: a frame supporting vertically
elevated and horizontally displaced pivots, a vertical plane
through the horizontal axis of said pivots defining a zero
position; a pair of single swing arms, each including a foot
platform rigidly secured thereto, rotatably coupled to respective
ones of said pivots; said single swing arms being interconnected to
cause alternating movement of said foot platforms in arcs through a
coincident position defined by said foot platforms being alongside
each other; and a bias system for biasing said swing arms such that
said coincident position is in front of said zero position, said
bias system including: a pulley arrangement rotatably mounted on
said frame; and a flexible link traversing said pulley arrangement
and engaging said foot platforms.
18. The machine of claim 17, wherein said bias system is adjustable
for changing the distance between said zero position and said
coincident position.
19. The machine of claim 18, wherein said distance between said
zero position and said coincident position is adjustable by
changing the length of said arcs.
20. The machine of claim 18, wherein said distance between said
zero position and said coincident position is adjustable by
changing the location of said pulley arrangement on said frame.
Description
BACKGROUND OF THE INVENTION AND PRIOR ART
[0001] The present invention relates generally to a novel exercise
machine that provides a motion that generally simulates climbing a
hill with hand weights. There have been many prior art exercise
machines for providing motions that simulate walking, stepping,
stair climbing, gliding, etc. A major consideration in designing
exercising machines is that of minimizing impact on the user's
knees ankles and back. For the home market, considerations of
importance are cost, variability of the intensity of workout
attainable, size of the apparatus, ease of use, stability and
storability, i.e., can the machine be easily collapsed and moved
out of the way, if desired.
[0002] The powered treadmill exercise machine has proven very
popular. The treadmill, like walking itself, has a significant
downside, namely it subjects the user's body to fairly large impact
forces. Glider type exercise machines, on the other hand, can
approach near zero impact. However, in order to achieve a good
workout, a glider may require large movements, which many users
find beyond their capabilities.
[0003] Glider exercise machines having single swing arms with
rigidly attached foot platforms are relatively simple and effective
for many users, yet they lack inherent stability. Some gliders have
a stationary handlebar to offer balance. In many gliders the swing
arms and foot platforms are interlocked so that they always move in
opposite directions. Many glider type machines have dual swing arms
that support the foot platforms in a parallelogram for adding
stability to the machine and flattening the foot platforms' travel
arc.
[0004] The art also includes many stepper type exercise machines,
some with interlocked foot platforms. Stepper machines generally
enable only up and down foot platform motion.
[0005] Another class of machines constrains the foot platforms to
an elliptical motion, resulting in a modified bicycle type action
that is favored by some users. These machines usually include
upright handles that are movable with the foot platforms for
providing balance and enabling upper body action. All of these
types of exercise machines have certain advantages, which their
advocates stress.
[0006] U.S. Pat. No. 6,004,244 to Simonson describes an exercise
machine that includes interlocked foot platforms that are suspended
from multiple swing arms with upright handles. The interlocking may
comprise a soft link, such as a rope, cable, chain, etc., or a hard
link, such as a rocker lever. The user, of course, can adjust his
length of stride within the fixed range of the arc. The suspension
of the foot platforms from the multiple swing arms keeps the foot
platforms substantially parallel to the ground throughout the
majority of their travel. The patent describes arrangements for
changing the machine loading. The loading mechanisms may comprise
alternator resistance, resistance devices, such as shock absorbers
or hydraulic devices, as well as means for relocating the
resistance devices so as to change the mechanical advantage. The
foot platforms of the system, and therefore the user's weight, are
biased out in front of the swing arm pivots. As the foot platforms
reciprocate through the travel arc, they reach a position where
they are alongside each other (the handles also align at this
point) and the foot platforms pass each other as the motion is
continued. The position of alignment is referred to in the patent
as the neutral position. The neutral position is in front of the
position defined by an imaginary vertical line through the swing
arm pivot. This latter position is directly below the swing arm
pivot, where gravity would bring the foot platform to a stop when a
user puts weight on only one of the free swinging foot platforms.
As will be described below, Applicants' exercise machine, while
similar in many respects to the patented machine, offers a
significantly different motion to the feet, ankles, hands and arms
of the user and gives rise to other benefits to be described.
[0007] A contemporary popular machine in club gyms is the Arc
Trainer by Cybex.RTM. International, Inc. as described in a
Giannelli Patent Application Publication US 2004/0224285 A1. (Both
the Simonson patent and the Giannelli publication are assigned to
Cybex.RTM. International, Inc.) The Giannelli publication uses
similar multiple swing arms for keeping the foot platforms
parallel. The machine includes upright handles that are
interconnected by a crank arm with the foot platforms. While the
crank mechanism is movable on the frame for adjusting the climbing
effect of the machine, the stride length is constant.
[0008] With the present invention exercise machine, a novel motion
is achieved which simulates a combination of walking uphill with
small hand weights. The machine includes single swing arms with
fixed foot platforms and forwardly extending, substantially
horizontal, handles that are affixed to the swing arms. The swing
arms and foot platforms are interlocked through a flexible link and
pulley arrangement. The flexible link may comprise a cable or a
rope, or any other similar type connection. A user may add an upper
body workout by simultaneously pulling or pushing on the horizontal
handles while moving the foot platforms. The machine also has
provision for adjusting the length of stride and the climbing
effect. The machine of the invention is well suited for the home
market due to its low cost, ease of use and stability.
Additionally, its design lends itself to be readily broken down for
shipping and storage.
OBJECTS OF THE INVENTION
[0009] A principal object of the invention is to provide a novel
exercise machine.
[0010] Another object of the invention is to provide a desirable
device motion with a low cost, small machine suitable to home
use.
[0011] Still another object of the invention is to provide a stable
exercise machine having interlocked single swing arms.
[0012] A further object of the invention is to provide an exercise
machine with a simple arrangement for changing workout
intensity.
[0013] A feature of the invention resides in the horizontally
forwardly extending handles interlocked with the foot platforms for
enabling vigorous upper and lower body exercising, as well as
moderate lower body workouts or low intensity shuffling.
[0014] Another feature of the invention resides in enabling the
length of the flexible link to be readily changed to alter the
length and height of stride.
[0015] A still further feature resides in the positioning of the
pulleys close to the ground at the front of the machine to enable
the foot platforms to pass thereover to reduce the machine's foot
print and to enhance its foldability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] These and other objects and features of the invention will
be apparent upon reading the following description in conjunction
with the drawings in which:
[0017] FIG. 1 is a left front perspective view of the exercise
machine of the invention;
[0018] FIG. 2 is a left side view of the exercise machine of FIG.
1.
[0019] FIG. 3 is a rear view of the exercise machine of FIG. 2;
[0020] FIG. 4 is partial view of one form of a pulley arrangement
taken along the lines 4-4 of FIG. 2;
[0021] FIG. 5 is a partial perspective view illustrating the load
changing mechanism;
[0022] FIGS. 6-11 illustrate differences between Applicants'
inventive device and the prior art;
[0023] FIGS. 12-15 illustrate foot platform movement paths for the
inventive device and the prior art;
[0024] FIG. 16 shows the pulley arrangement in the inventive device
that enables a "fold up" design;
[0025] FIG. 17 is a top view of the exercise machine of the
invention modified to function with a single pulley; and
[0026] FIG. 18 is a partial view of FIG. 17 illustrating the
flexible link adjustment in an exercise machine having a single
pulley arrangement.
SUMMARY OF THE INVENTION
[0027] The invention comprises an exercise machine including single
swing arms with fixed foot platforms and forwardly extending,
substantially horizontal, handles that are affixed to the swing
arms. The swing arms and foot platforms are interlocked through a
flexible link and pulley arrangement. The machine includes means
for adjusting the maximum travel arc of the foot platforms, which
also changes the climbing effect of the exercise machine.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] The following description is best read in conjunction with
FIGS. 1-3 of the drawings. A left front leg 12 and a right front
leg 14, connected by a cross tube 17, cooperate with a U-shaped
rear leg 15 to provide a frame for exercise machine 10. The open
ends of U-shaped rear leg 15 are pivotally connected to front legs
12 and 14 (slightly more than half way up legs 12 and 14) and are
joined thereto by a pivotal connection 24 in plates 20,20' and a
pivotal connection 26 in plates 22,22', respectively. The legs are
preferably constructed of tubular steel. The plates 20,20' and
22,22' are preferably welded to front legs 12 and 14, respectively.
It will be appreciated that all rigid mechanical connections on the
exercise machine are preferably accomplished by welding, although
any other appropriate form of connecting the parts is acceptable.
Cross tube 17 is connected, by welding, to front legs 12 and 14
near their lower ends. A left swing arm 28 and a right swing arm 30
are pivotally mounted on pivots 40 and 42, which are secured, by
any well-known means, to the upper ends of front legs 12 and 14,
respectively. Foot platforms 32 and 34 are affixed to two
extensions 32a and 34a that are welded to the bottoms of respective
ones of swing arms 28 and 30.
[0029] Two forwardly extending horizontal handles 16 and 18 are
secured to pivots 40 and 42, respectively. Thus, handle 16 and
swing arm 28 are rotatable on pivot 40, and handle 18 and swing arm
30 are rotatable on pivot 42. A pair of flexible braces 36 and 38
(affixed to front legs 12 and 14, by suitable fittings such as
fittings 36a,36b) connect legs 12 and 14 together to provide an "A
frame" type of support for machine 10. The flexibility of braces 36
and 38, as will be seen, contribute to the foldability of machine
10. In this connection, it will be appreciated that the term
flexibility also includes pivotable linkages such as those employed
in folding step stools, and the like. Pivots 40 and 42 include
extension plates 44 and 46, respectively, for providing pivotal
connections to first ends of resistance devices, such as
conventional shock absorbers 48 and 50, respectively, with the
other ends of the resistance devices being pivotally connected to
plates 20,20' and 22,22' at hinge points 52 and 54, respectively.
Suitable bushings 48a,48b and 50a,50b couple the ends of shock
absorbers 48 and 50 to hinge points 52 and 54, respectively.
[0030] A pair of pulley devices 56 and 58 is secured behind cross
tube 17 to the inside lower portions of front legs 12 and 14,
respectively. A flexible link 19 engages pulley devices 56 and 58
and is attached at one end to the heel of foot platform 32 via a
pivotally mounted guide 60. The other end of flexible link 19 is
passed over a pivotally mounted guide 62 on the heel of foot
platform 34 and secured to an adjustment mechanism 70, that is
affixed to the lower end of swing arm 30. Finally, two rollers 64
and 66, which are normally out of contact with the floor, are
secured to the base portion of U-shaped rear leg 15 to facilitate
movement of the exercise machine.
[0031] FIG. 4 is a partial view showing pulley device 56. It
includes a U-shaped frame 56a, housing a pulley 56b, that is
rotatably mounted on an axle pin 56c. Frame 56a is, in turn,
rotatably mounted on a cylindrical rod 56d that is welded to the
inside of front leg 12. Flexible link 19 passes over pulley 56b and
is captivated within frame 56a. It will be appreciated that a
similar arrangement obtains for pulley device 58 with respect to
front leg 14. The hinging movement of pulley device 56 on
cylindrical rod 56d permits its angular alignment to the flexible
link 19. The arrangement allows the front portion of foot platform
32 to overlap pulley device 56 and enables the exercise machine to
be constructed with a smaller "footprint", which is an important
feature for home use. It also makes it feasible to fold the machine
for shipping and for storage.
[0032] FIG. 5 is a partial view illustrating adjustment mechanism
70 which consists of a block 72 that is secured along the lower
portion of swing arm 30. Block 72 includes a number of spaced
apertures 74 along its length. A conventional pin arrangement 76,
to which the end of flexible link 19 is connected, is removably
engageable with any of the apertures 74 in block 72. The aperture
74 in which pin arrangement 76 is secured thus determines the
effective length of flexible link 19 that interconnects the foot
platforms 32 and 34 and therefore establishes the maximum stride
length. When pin arrangement 76 is in the topmost one of apertures
74, the effective length of flexible link 19 is at a minimum,
whereas its effective length is at a maximum when the pin
arrangement is in the lowermost one of apertures 74. As will be
discussed, machine stride height is also impacted by changes in the
adjustment mechanism.
[0033] The arrangement whereby the foot platforms are
interconnected through the flexible link and pulley devices is
described as a bias system which, as will be discussed further,
establishes a "coincident position" in which the foot platforms are
side-by-side. The location of this point, which is adjustable by
repositioning the pulley device or devices, is always in front of a
"zero position" that is determined by a vertical line through the
axis of the pivots. With the single swing arms of the inventive
device, a novel motion is obtained that simulates a combination of
walking and stair climbing While in the two pulley implementation
of the invention the pulleys need to rotate about a single axis, in
the single pulley implementation, movement is required about
multiple axes. It will also be appreciated that, while in the
implementation of the invention the pulley devices are rotatably
mounted to accommodate changes in angle of the flexible link during
operation of the machine, such changes in angularity may also be
accommodated by the use of pulleys with wide spool sheaves. While
the machine layout described is preferred, it will also be readily
apparent that other implementations of the invention are
contemplated.
[0034] FIGS. 6-11 are referenced to explain the unique motion
achieved with Applicants invention. FIG. 6 shows Applicants'
coincident position. This position is attained by the user standing
with his weight distributed equally on the foot platforms of the
exercise machine. It will be seen that the user's center of weight,
i.e., a vertical line through the user's center of gravity, is
biased in front of pivot 42 of the exercise machine. It will be
seen that Applicants' coincident position corresponds to the
neutral position discussed in the Simonson patent. In FIG. 7,
Applicants' zero position is attained when the user places all of
his weight on only one of the foot platforms. In Applicants'
machine, the zero position is attainable by the user at all times,
which is an important aspect of the invention.
[0035] While the Applicants', the Giannelli publication's and the
Simonson patent's exercise machines all bias the user's weight out
in front of the swing arm pivots, Applicants' use of single swing
arms with fixed foot platforms, versus the Giannelli' publication's
and the Simonson patent's use of parallelogram type multiple swing
arms for keeping the foot platforms generally parallel to the
ground, yields significantly different effects on the user's calf
muscles, as shown in FIGS. 8 and 9. Specifically, with Applicants'
single swing arm system, the user's calf muscles are activated to a
much greater extent than they are with the Giannelli publication's
and the Simonson patent's parallelogram type multiple swing arms.
Whereas, for example the user's ankles are flexed between
approximately 100.RTM. and 80.degree. in Applicants' machine, the
user's ankles barely flex at all in the Giannelli publication's and
the Simonson patent's machine, remaining at approximately
90.degree. throughout.
[0036] Applicants' forwardly extending horizontal handles also have
a marked impact on the operation of their machine. As shown in FIG.
11, with the invention, should a user desire a strenuous arm
workout, he may readily use his body weight to counter his pushing
and pulling on the horizontal handles, thus enabling a significant
working of his triceps. On the other hand the user may opt to
gently pull up on the handles to help propel the machine, resulting
in a hand motion very similar to walking with small weights.
Specifically, the hands move in an arc that is centered just below
the user's elbow. The user is also lifting against his feet, which
maintains an upward pull during the eccentric and concentric
motions of the biceps (extension and contraction of the muscle).
Also, positioning the handles horizontally at about the hip level
of an average user allows the user to use a very natural motion,
specifically to put his weight on his hands, similar to what people
on crutches (or older folks with walkers) must do to maintain a
continuous load in one direction. In the Giannelli publication and
the Simonson patent, (FIG. 10) the handles are out front and
upright, and each arm must counter the other, alternating between
pushing and pulling with each stroke. This results in considerable
twisting of the user's torso, which is uncomfortable, and generally
discourages the user from working his arms very much.
[0037] Another important aspect of the invention is its bias
adjustment system. Reference to FIGS. 12 and 13, representing the
Giannelli system and FIGS. 14 and 15 representing the present
invention system, will illustrate this aspect of the invention. The
Giannelli system uses a momentum wheel that is connected by a crank
to the multiple swing arms. The momentum wheel is adjustable, back
and forth, in order to change the angular position of the arc that
the user's feet move in, namely, lower in the arc (closer to the
zero position) for less climbing motion and higher in the arc for
more climbing motion. However, the Giannelli system has a fixed
length of stride that is dictated by the crank. Therefore,
adjustment of the crank wheel position changes both the top and
bottom points of the stride. This is clearly illustrated by FIGS.
12 and 13.
[0038] Applicants' system, to the contrary, has a variable stride
length, which the user chooses. Changes in the length of the
flexible link or changes in pulley position (as is shown FIG. 17)
result in changing the coincident position of the foot platforms;
but the user can still stride all the way to the zero position (or
even past the zero position if he pushes back at the end of the
stride). The tendency to follow each step to the zero position is a
natural one, which gives the user the feeling of a complete step.
At the bottom of the stride the user feels the foot platform
smoothly bottom out, signaling that it is time to transfer his
weight to the other foot. If he does not step back to the zero
position, the sensation is unnatural, like walking with bent knees.
Therefore, with the invention an adjustment in the coincident
position also results in an effective change of stride length when
the user naturally follows through to the zero position.
[0039] Applicants have learned from long experience with their
commercial glider exercise machines that many less-fit users prefer
a short shuffling action. Shuffling is a relatively low effort
movement that depends upon stepping only a short distance to and
from the zero position, and is readily achieved with the inventive
machine by adjusting the coincident position rearward (toward the
zero position). Conversely, adjusting the coincident position
forward (away from the zero position) results in a longer stride.
This produces a much higher step at the top of the stride, thus
working the quadriceps harder and intensifying the cardio workout.
It will be noted that when shuffling is achieved by effectively
lengthening the flexible link, a longer stride is actually
achievable by the user pushing back past the zero position,
although this is an unnatural movement and will probably be avoided
by most users, therefore resulting instead in a shorter stride.
[0040] In operation, a user steps on the foot platforms 32 and 34
while grasping the handles 16 and 18. When the user is in a rest or
idle position, i.e., standing with weight equally distributed on
the foot platforms, his center of weight will be biased forward of
the horizontal axis defined by the pivots 40 and 42 (the coincident
position). This relationship is determined by the effective length
of flexible link 19 and is selected in this invention to produce
this bias even at its maximum length setting, which is with pin
arrangement 76 in the lowermost aperture 74. As the user performs
his exercise, he may elect to engage his arms by simultaneously
pushing down or pulling up on the horizontally extending handles 16
and 18. This is not only beneficial for the user's upper body, but
provides a feeling of stability in normal use of the machine,
similar to the effect experienced with a conventional walker, where
the user uses his arms to aid his walking movements. It will also
be appreciated that the single swing arm arrangement provides a
distinct travel arc, which exercises the user's ankles and feet
more than is possible with foot platforms suspended in a
parallelogram from multiple swing arms. Also, it will be seen that
the pulleys are positioned below the travel arc of the foot
platforms, which enables the foot platforms to pass thereover
without interference. This makes for a very compact design which
also lends itself to foldability, which is often desirable for home
use.
[0041] This feature is better illustrated in FIG. 16 where the
positioning of the pulley device is low to the floor and below the
travel arc of the foot platforms. The small machine footprint and
the "A frame" construction also enhance the machine's foldability.
For example, provision for removable (or inwardly rotatable)
handles and a fold up arrangement for the foot platforms results in
a very compact machine for shipping or storage.
[0042] In FIG. 17 a single pulley implementation of the exercise
machine is shown. The single pulley 66a consists of an elongated
U-shaped frame 66b, with aligned apertures in each leg, connected
to cross tube 17 by a conventional swivel connection 66c that
enables up and down and rotational motion. A pulley sheave 66d is
removably secured in one of the apertures by a pin mechanism 66e.
Adjustment of the coincident position is obtained by repositioning
the pulley in the U-shaped frame apertures. The flexible link 19
has its ends coupled to the inside heels of the foot platforms 32
and 34 for clearance purposes.
[0043] FIG. 18 illustrates an alternative technique for adjusting
flexible link 19. In this embodiment, the apertures 74a are formed
in the side of foot platform 34 and flexible link 19 is guided
along the side by fitting 62. A pin arrangement 76a secures the end
of flexible link 19 in the desired one of apertures 74a. It should
be noted that only a single one of the two methods of adjusting the
bias will be employed in a given machine, although both may be
used, if desired. It will be appreciated that the invention is not
dependent upon such details and is to be limited only as defined in
the claims.
* * * * *