U.S. patent number RE40,875 [Application Number 11/292,384] was granted by the patent office on 2009-08-18 for controllable load apparatus.
This patent grant is currently assigned to BMR Research & Development Limited. Invention is credited to Conor Minogue, Seamus Moneley, Brian Walsh.
United States Patent |
RE40,875 |
Minogue , et al. |
August 18, 2009 |
Controllable load apparatus
Abstract
The invention relates to a controllable load apparatus for use
in machines for resistive exercise training of the human body. The
apparatus comprises a pneumatic cylinder (10) having a piston (12)
acting on a fluid and a piston rod (14), the piston/cylinder unit
(10, 12) being operated on by a person undergoing training. A
pressure accumulator (20) is connected to, and pressurizes the
piston/cylinder unit (10, 12) at a predetermined pressure during
exercise via a pneumatic control circuit (42). Once a predetermined
pressure threshold is reached, a valve means operates to prevent
further fluid being available for charging the accumulator
(20).
Inventors: |
Minogue; Conor (Galway,
IE), Walsh; Brian (Galway, IE), Moneley;
Seamus (County Mayo, IE) |
Assignee: |
BMR Research & Development
Limited (Galway, IE)
|
Family
ID: |
9947643 |
Appl.
No.: |
11/292,384 |
Filed: |
December 1, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
10316410 |
Dec 9, 2002 |
06939275 |
Sep 6, 2005 |
|
|
Foreign Application Priority Data
|
|
|
|
|
Nov 12, 2002 [GB] |
|
|
0226325 |
|
Current U.S.
Class: |
482/110; 482/111;
482/112 |
Current CPC
Class: |
A63B
21/0083 (20130101); A63B 21/0087 (20130101); A63B
21/00069 (20130101); A63B 24/00 (20130101) |
Current International
Class: |
A63B
21/00 (20060101) |
Field of
Search: |
;482/1-9,92,110-113,148,900,901 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Richman; Glenn
Attorney, Agent or Firm: Drinker Biddle & Reath LLP
Claims
What is claimed is:
1. A controllable load apparatus for use in resistive exercise
training the apparatus comprising a fluid piston/cylinder unit
which, in use, is operated on by a person undergoing training, a
pressure accumulator connected to pressurise the piston/cylinder
unit at a predetermined pressure during exercise, and pressure
setting means for setting said predetermined pressure in the
pressure accumulator; and in which the piston/cylinder unit is in
communication with the accumulator through a pneumatic control
circuit which in an initial mode permits operation of the
piston/cylinder unit by a user to initially pressurise the
accumulator with ambient air to said predetermined pressure, and in
a working mode connects the same piston/cylinder unit directly to
the accumulator for training.
2. Apparatus according to claim 1, wherein the pressure setting
means comprises a changeover valve within the pneumatic control
circuit which operates at a predetermined pressure to prevent
further fluid being available for charging the accumulator.
3. Apparatus according to claim 2, in which the changeover valve is
an electrically operated valve which may be controlled by an
electronic circuit or program device.
4. Apparatus according to claim 1, in which the working fluid is
air.
5. Apparatus according to claim 1, in which the cylinder is fixed
and the piston is moved by the user.
6. Apparatus according to claim 1, in which the piston is a plain
piston.
7. Apparatus according to claim 1, in which the piston is provided
with a valve or restrictor such that the piston/cylinder unit acts
in the manner of a gas strut to provide a substantially constant
force throughout the stroke.
8. Apparatus according to claim 1, in which said piston/cylinder
unit comprises twin pistons which are coupled together for normal
use and which are decoupled to provide a reduced area for initially
pressurising the accumulator.
Description
FIELD OF THE INVENTION
This invention relates to a controllable load apparatus for use in
machines for resistive exercise training of the human body.
BACKGROUND OF THE INVENTION
It is well known to exercise the body for purposes of muscle
strength training by way of resistive training, that is where a
selected muscle or group of muscles is exercised against a
mechanical resistance. The training may be (a) isometric, in which
the muscle length remains constant and the associated joint angle
remains constant, (b) isotonic, in which the muscle shortens or
lengthens at a constant force throughout the range of movement: the
external force may change such that the muscle force remains
constant as the mechanical advantage varies with joint angle, (c)
DCER (Dynamic Constant External Resistance), in which the external
force is constant and the muscle force may change with different
joint angles, and (d) isokinetic, in which the joint angular
velocity is constant and the muscle force varies with varying joint
angle. It is therefore apparent that it is desirable to be able to
change the force-displacement characteristics of a resistance
training device.
It is also known to prescribe an exercise regime in terms of a
number of repetitions of a force equal to a stated percentage of
the maximum force which that subject can exert, which will
obviously vary between subjects and over time.
There is therefore a need to provide exercise apparatus in which a
resistive force can readily be varied for different subjects,
different muscles within a given subject, or during the carrying
out of a particular type of exercise. An object of the present
invention is to provide a controllable load apparatus which would
be useful in such an application.
Resistance training devices are known in the art which operate on
the principle of compressing a gas, usually air. These devices
require the provision of a compressed air supply which is used to
precharge a cylinder to a starting pressure, and corresponding
starting resistance, using a pressure regulator. Such a source of
compressed air is not practical in a portable exerciser.
U.S. Pat. No. 4,880,230 describes a pneumatic exerciser comprising
a double acting cylinder where the resistance is controlled by
restricting the air flow between the chambers on either side of the
piston. The resistive force of such a system is highly dependent on
the velocity of activation, since it is based on flow
restriction.
U.S. Pat. No. 4,257,583 describes a pneumatic exercise device which
uses an air compressor to charge pressure reservoirs.
SUMMARY OF THE INVENTION
Accordingly, the invention provides a controllable load apparatus
for use in resistive exercise training, the apparatus comprising a
fluid piston/cylinder unit which, in use, is operated on by a
person undergoing training, a pressure accumulator connected to
pressurise the piston/cylinder unit at a predetermined pressure
during exercise, and pressure setting means for setting said
predetermined pressure in the pressure accumulator.
In a preferred form of the invention the accumulator is pressurised
by the user operating the piston/cylinder unit and the pressure
setting means comprises a changeover valve which operates at a
predetermined pressure to prevent further fluid being available for
charging the accumulator. Said valve is preferably an electrically
operated valve which may be controlled by an electronic circuit or
program device.
The working fluid will typically be air. However, other gases may
be used, as may liquids.
Typically, the cylinder will be fixed and the piston moved by the
user, but the inverse is also possible.
The piston may be a plain piston, or may be provided with a valve
or restrictor such that the piston/cylinder unit acts in the manner
of a gas strut to provide a substantially constant force throughout
the stroke.
The apparatus may include piston/cylinder means of reduced area for
use in initially pressurising the accumulator.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of
example only, with reference to the drawings, in which:
FIG. 1 is a general schematic of one form of the invention;
FIG. 2 is a schematic diagram of the pneumatic circuit of an
apparatus forming a first embodiment of the invention;
FIG. 3 is a similar diagram of a second embodiment;
FIG. 4 illustrates a modification of the embodiment of FIG. 1;
FIG. 5 shows an alternative modification; and
FIG. 6 shows, in simplified form, a further embodiment.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to FIG. 1, the apparatus in general terms comprises a
pneumatic cylinder 10 having a piston 12 and piston rod 14, the
cylinder 10 being connected through a pneumatic control circuit 42
to a pressure accumulator 20.
In a simple form of the invention as shown in FIG. 2, the piston
rod 14 forms a movable load-resisting member to which a user
applies forces via a linkage (not shown). The cylinder 10 is
connected through a changeover valve 16 and a one-way valve 18 to
the pressure accumulator 20.
Starting from a discharged state, repeated strokes of the piston 12
compress air drawn in through intake valve 22 and the pressure
builds in the accumulator 20. When a given target pressure has been
reached, the valve 16 switches, thus connecting the cylinder 10
directly to the accumulator 20. In this condition, the force
required to move the piston rod 14 depends on the elevated pressure
in the system, and repeated exercises at this elevated resistance
level can be carried out.
The valve 16 is preferably actuated electrically, which permits an
electronic control circuit to set a desired force level or program
of force levels. Alternatively, the valve 16 could be operated by a
mechanical force setting system.
When exercise is completed, the system can be discharged by
operating exhaust valve 24. A pressure relief valve 26 protects the
system against over-pressure.
The foregoing embodiment can readily be extended to more than one
cylinder operating in series or parallel. Moreover, it can easily
be arranged to offer resistance in extension or compression or both
by suitable porting of the cylinders.
FIG. 3 illustrates an exercise apparatus which can offer resistance
in extension or compression. In FIG. 3 parts which are similar to
those of FIG. 2 bear like reference numerals and will not be
further described.
In this embodiment there are two cylinders 10a, 10b and
corresponding pistons 12a, 12b and piston rods 14a, 14b. Valve 16
is replaced by a changeover valve 28 and an on-off valve 30. The
charging of the pressure accumulator 20 can be achieved with the
valves 28, 30 in the position shown. Resistance to compression is
achieved with both valves 28 and 30 activated, and resistance to
extension with valve 30 activated and valve 28 as shown.
Charging the accumulator to a high pressure required for operation
can create a problem in that the subject may not be able to
generate enough force on the piston rod to produce the required
pressure. FIG. 4 shows one way of overcoming this problem. The
cylinder 10 is provided with a modified piston 12a which comprises
an outer piston 32 with an inner piston 34 nested telescopically
therein. In normal use, the pistons 32, 34 are latched together and
operate as a normal piston. For ease in generating the required
high pressure, the outer piston 32 is placed in the closed
position, the inner piston 34 is unlatched from the outer piston
32, and the inner piston is operated by the user to charge the
accumulator. Because of the smaller area of the inner piston 34,
the force required to achieve the desired pressure is reduced.
Equally, the area of the outer piston 32 could be smaller and a
similar principle employed.
The inner and outer pistons may be latched together by a user
operable hand control, or alternatively under electrical control
using a solenoid operated pin, a clutch or a rotating actuator.
FIG. 5 shows another way of achieving the same effect. Here, the
cylinder 10 is replaced by a relatively large diameter cylinder 36
and a relatively small cylinder 38. The piston rods of these two
cylinders are mechanically coupled at 40, but can be decoupled to
allow the smaller cylinder to operate alone.
The relationship of force to displacement is determined by the
volume of the cylinder, the volume of the accumulator, and the
initial pressure of the cylinder and accumulator. It follows the
gas equation P1V1=P2V2, where P1 is the starting pressure, P2 is
the end pressure, V1 is the starting volume (in this case the
combined volume of the cylinder and accumulator), and V2 is the end
volume (in this case the volume of the accumulator alone).
The force-displacement characteristic follows the
pressure-displacement characteristic since
Force=Pressure.times.Area of Piston. This assumes that a
conventional piston is used, and not a gas strut piston
incorporating a pressure equalising valve.
Consider now in detail the sequence of actions required to exercise
to a force of say 50 kgf. If the diameter of the piston is 3.5 cm
then the area of the piston is 9.6 cm.sup.2. The pressure at 50 kgf
is therefore 50/9.6=5.2 bar. Assume the stroke length of the piston
is 20 cm, and consequently the volume of air displaced is 192
cm.sup.3, or say 0.19 litres.
An accumulator with a volume of 0.5 litre will be charged to 5.2
bar in approximately 14 strokes. When the apparatus is switched
from the charge mode to the exercise mode the accumulator is
connected to the cylinder and the piston rod extends (or retracts,
depending on the required exercise). The pressure now reduces to
3.8 bar, assuming the changeover occurred at the end of a
compressive stroke. Each subsequent exercise stroke therefore
starts at 3.8 bar corresponding to 36 kgf and rises to 5.2 bar
corresponding to 50 kgf at the end of the stroke.
It is apparent that, if a plain piston and cylinder is used in the
apparatus of the present invention, a constant resistive force will
not be achieved.
A constant resistive force can be provided by replacing the piston
and cylinder with a gas strut type of device, as illustrated in
principle in FIG. 6. In FIG. 6, the piston and cylinder 10, 12 is
replaced by a gas strut device 40, which is connected to the
accumulator 20 via charge and control circuitry indicated generally
at 42. The gas strut device 40 comprises a cylinder 42, piston 44
and piston rod 46, the piston having a restricted aperture 48
therethrough.
A gas strut device provides a resistive force based on gas
pressure. It is a closed system whereby the gas on the compression
side of the piston leaks to the lower pressure side as the load is
applied through valves or restrictions in the piston. In effect the
pressure equalises either side of the piston and the residual force
is derived from the unequal areas on either side of the piston; the
piston rod reduces the effective area of the piston on its side. A
gas strut therefore approximates to a constant force device, and
the force level is determined by the gas pressure.
In the embodiment of FIG. 6, the initial pressurisation is produced
by the user charging the accumulator 20 as described above, and in
the exercise mode the user experiences a substantially constant
force the amplitude of which is set by the level of the initial
pressurisation.
The invention thus provides an exercise apparatus in which
resistance ben set and controlled in a simple and convenient
manner. In particular forms of the invention there can be achieved
(a) a variety of force-displacement characteristics, parameterised
by the starting force at the beginning of the stroke, the end force
at the end of the stroke, and a number of points in between, (b) a
range of force-displacement characteristics, and (c) no requirement
for a separate compressed air supply.
Modifications may be made to the foregoing embodiments within the
scope of the invention. For example an electric pump may be
provided for effecting the initial charging of the pressure
accumulator.
* * * * *