Title: Self-actuating control valve for a bed pad or seat pad
Abstract: A fluid operated control valve for controlling fluid flow of a system which includes a first and a second fluid channels therein, the control valve includes: a hollow casing with closed first and second ends; a piston member slidably disposed within the casing and defining thereby within the casing a first chamber adjacent to the first end of the casing and a second chamber adjacent to the second end of the casing; a first magnet disposed adjacent the first chamber of the casing for attracting the piston member to a first terminal position; a second magnet disposed adjacent the second chamber of the casing for attracting the piston member to a second terminal position. The control valve further includes: an input port disposed adjacent to an intermediate location in the casing; a first output port disposed in the casing in fluid communication with the first chamber; a second output port disposed in the casing in fluid communication with the second chamber; wherein the control valve is adapted to alternately inflate and deflate the two fluid channels of the system through the ports in response to the reciprocal movement of the piston member. Pad systems utilizing the control valve are also disclosed.
Patent Number: 6,895,988 Issued on 05/24/2005 to Grant, et al.
| Inventors:
|
Grant; Benton H. (Stamford, CT);
Ward; Kenneth A. (Dorset, VT)
|
| Assignee:
|
Grant Airmass Corporation (Stamford, CT)
|
| Appl. No.:
|
435089 |
| Filed:
|
May 9, 2003 |
| Current U.S. Class: |
137/119.01; 5/713; 137/119.02; 137/119.09; 297/284.6 |
| Intern'l Class: |
G05D 007/01 |
| Field of Search: |
137/11901,119.02,119.08,119.09,102,106,624.2
5/713
297/284.6
|
References Cited [Referenced By]
U.S. Patent Documents
| 3465686 | Sep., 1969 | Nugier.
| |
| 3495620 | Feb., 1970 | Raimondi et al.
| |
| 3527248 | Sep., 1970 | Western-Pick.
| |
| 3592230 | Jul., 1971 | Piroutek.
| |
| 3623695 | Nov., 1971 | Hislop.
| |
| 3734132 | May., 1973 | Kuhnelt.
| |
| 3797520 | Mar., 1974 | Lekarski et al.
| |
| 4112962 | Sep., 1978 | Huff.
| |
| 4203571 | May., 1980 | Ruchser.
| |
| 4285268 | Aug., 1981 | Deckler.
| |
| 4635681 | Jan., 1987 | Boldish.
| |
| 5135282 | Aug., 1992 | Pappers.
| |
| 5272778 | Dec., 1993 | Gore.
| |
| 5320136 | Jun., 1994 | Morris et al.
| |
| 5377719 | Jan., 1995 | Gyllinder, et al.
| |
| 5584085 | Dec., 1996 | Banko.
| |
| 5659908 | Aug., 1997 | Nishino.
| |
| 6370716 | Apr., 2002 | Wilkinson.
| |
Primary Examiner: Hepperle; Stephen M.
Attorney, Agent or Firm: St. Onge Steward Johnson & Reens LLC
Parent Case Text
This application claims the benefit of Provisional Application No. 60/409,636,
filed Sep. 10, 2002.
Claims
1. A fluid operated control valve for controlling fluid flow of a system, the
control valve comprising:
a hollow casing with closed first and second ends;
a piston member slidably disposed within the casing and defining thereby within
the casing a first chamber and a second chamber, each chamber having a volume variable
depending upon the position of the piston member;
a first magnetic member disposed adjacent the first casing end for attracting
the piston member to a first terminal position;
a second magnetic member disposed adjacent the second casing end for attracting
the piston member to a second terminal position;
an input port disposed adjacent to an intermediate location in the casing for
receiving operating fluid thereto;
a first output port disposed in the casing in fluid communication with the first
chamber;
a second output port disposed in the casing in fluid communication with the second
chamber; and
a passageway for alternately guiding the operating fluid from the input port
to the first chamber and the second chamber depending upon the position of the
piston member within the casing, the position of the piston being reciprocally
moveable between the two terminal positions when pressure difference between a
pressurizing chamber and the other chamber reaches a pressure overcoming attracting
force between the piston member and the one then-holding magnetic member.
2. The control valve of claim 1 further including a first vent port disposed
between the input port and the first output port, and a second vent port disposed
between the input port and the second output port, respectively, for venting fluid
from the chambers.
3. The control valve of claim 1, wherein the passageway includes a pair of conduits
for the alternate guiding of the fluid.
4. The control valve of claim 3, wherein the conduits are disposed in the piston member.
5. The control valve of claim 3, wherein the piston member further includes a
first and a second grooves each disposed at least partially around the circumference
of the piston member and respectively in communication with the first and the second
conduits for guiding the operating fluid.
6. The control valve of claim 1, wherein the first and second magnetic members
each include a magnet disposed within the respective chamber and a mating iron
slug attached to the piston member.
7. The control valve of claim 6, wherein the magnets are adjustable along to
the axial direction.
8. The control valve of claim 7, wherein the cycle of the pressurization of each
channel of the system is adjustable by adjusting the positioning of the magnets.
9. The control valve of claim 7, wherein maximum pressure of each channel of
the system is adjustable by adjusting a valve adapted to control the fluid flow
rate into the input port.
10. The control valve of claim 7, wherein the cycle of the pressurization of
each channel of the system is adjustable by adjusting a valve adapted to control
the vent rate of the system.
11. The control valve of claim 6 further including adjustment screws for the
adjustment of the axial position of the magnets.
12. The control valve of claim 6 further including first and second stop members
disposed respectively within the first and the second chamber for limiting the
terminal positions of the piston member.
13. The control valve of claim 12, wherein the first and second stop members
are protrusions extending axially from the respective first and second casing ends.
14. The control valve of claim 1 further including a seal disposed between the
casing and the piston member.
15. The control valve of claim 14, wherein the seal includes three O-ring members,
a first one disposed adjacent to an intermediate location of the piston member,
and a second and a third ones disposed respectively adjacent to each end of the
piston member.
16. The control valve of claim 15, wherein the O-ring members are moveable to
the axial direction along the piston member upon axial movement of the piston member.
17. The control valve of claim 16, wherein the first O-ring member is rollable
between a position located on the left of the input port and a position located
on the right of the input port, the second O-ring member is rollable between a
position located on the left of the first vent port and a position located on the
right of the first vent port, and the third O-ring member is rollable between a
position located on the left of the second vent port and a position located on
the right of the second vent port.
18. The control valve of claim 16, wherein the O-ring members are rollable within
grooves provided along the circumference of the piston member.
19. The control valve of claim 1, wherein the hollow casing and the piston member
are made of plastic material.
20. The control valve of claim 1, wherein the hollow casing and the piston member
are made of metal.
21. The control valve of claim 1, wherein the operating fluid is air.
22. A fluid operated control valve for controlling fluid flow of a system, the
control valve comprising:
a hollow casing with closed first and second ends;
a piston member slidably disposed within the casing and defining thereby within
the casing a first chamber and a second chamber, each chamber having a volume variable
depending upon the position of the piston member;
a first magnetic member disposed adjacent the first casing end for attracting
the piston member to a first terminal position;
a second magnetic member disposed adjacent the second casing end for attracting
the piston member to a second terminal position;
an input port disposed adjacent to an intermediate location in the casing for
receiving operating fluid thereto;
a first output port disposed in the casing in fluid communication with the first
chamber;
a second output port disposed in the casing in fluid communication with the second
chamber; and
a passageway for alternately guiding the operating fluid from the input port
to the first chamber and the second chamber depending upon the position of the
piston member within the casing, the position of the piston being reciprocally
moveable between the two terminal positions when a pressurizing chamber reaches
a maximum pressure overcoming attracting force between the piston member and the
one then-holding magnetic member.
23. A fluid operated control valve for controlling fluid flow of a system, the
control valve comprising:
a hollow casing with closed first and second ends;
a piston member slidably disposed within the casing and defining thereby within
the casing a first chamber and a second chamber, each chamber having a volume variable
depending upon the position of the piston member;
a first magnetic member disposed adjacent the first casing end for attracting
the piston member to a first terminal position;
a second magnetic member disposed adjacent the second casing end for attracting
the piston member to a second terminal position;
an input port disposed adjacent to an intermediate location in the casing for
receiving operating fluid thereto;
a first output port disposed in the casing in fluid communication with the first
chamber;
a second output port disposed in the casing in fluid communication with the second
chamber; and
a passageway for alternately guiding the operating fluid from the input port
to the first chamber and the second chamber depending upon the position of the
piston member within the casing, the position of the piston being reciprocally
moveable between the two terminal positions when a venting chamber reaches a minimum
pressure.
24. An amenity system for use with a fluid source for providing operating fluid
to the system, comprising:
an amenity member including a first and a second fluid channels therein; and
a control valve disposed in fluid communication with the fluid source and the
fluid channels of the amenity member and for alternately inflating and deflating
the fluid channels, the control valve including:
a hollow casing with closed first and second ends;
a piston member slidably disposed within the casing and defining thereby within
the casing a first chamber adjacent to the first end of the casing and a second
chamber adjacent to the second end of the casing, each chamber having a volume
variable depending upon the position of the piston member;
a first magnetic member disposed adjacent the first chamber for attracting the
piston member to a first terminal position;
a second magnetic member disposed adjacent the second chamber for attracting
the piston member to a second terminal position;
an input port disposed adjacent to an intermediate location in the casing for
receiving the operating fluid thereto from the fluid source;
a first output port disposed in the first chamber in fluid communication with
the first chamber and the first fluid channel of the amenity member;
a second output port disposed in the second chamber in fluid communication with
the second chamber and the second fluid channel of the amenity member; and
a passageway for alternately guiding the operating fluid from the input port
to the first chamber and the second chamber depending upon the position of the
piston member within the casing, the position of the piston being reciprocally
moveable between the two terminal positions when pressure difference between a
pressurizing chamber and the other chamber reaches a pressure overcoming attracting
force between the piston member and the one then-holding magnetic mating member,
thereby allowing alternate pressurizing of the fluid channels of the amenity member.
25. The amenity system of claim 24 further including a first vent port disposed
between the input port and the first output port, and a second vent port disposed
between the input port and the second output port, respectively, for venting fluid
from the chambers.
26. The amenity system of claim 24 utilized for a bed pad system.
27. The amenity system of claim 26, wherein the amenity member is a bed pad.
28. The amenity system of claim 24 utilized for a seat pad system.
29. The amenity system of claim 28, wherein the amenity member is a seat pad.
30. The amenity system of claim 24, wherein the passageway of the control valve
includes a pair of conduits disposed in the piston member for the alternate guiding
of the fluid.
Description
FIELD OF THE INVENTION
The present invention relates generally to control valves for controlling fluid
flow of a system. In particular, the present invention relates to fluid operable,
self-actuating control valves usable for various systems such as pad systems (e.g.,
bed pad or seat pad systems) and comfort systems, etc.
BACKGROUND OF THE INVENTION
Bed pads and seat pads are sometimes employed in medical settings to prevent
bed sores or used to reduce fatigue and provide comfort in situations where prolonged
sitting or resting in one place is required. These devices function by repeatedly
and alternately inflating and deflating adjacent air channels in the pad or cushion
so that the supporting pressure on any one part of the human body is in constant change.
In such known pad systems, the directing of the required air pressure is accomplished
by use of a timer operated by alternating current (e.g., 60 hz) and a valve which
is electrically operated as directed by the timer. This dependence on alternating
current is costly and a great disadvantage particularly in an application (such
as a wheelchair or automobile) where alternating current is not available.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to fluid operable, self-actuating
control valves usable for various systems, such as pad systems (e.g., bed pad and
seat pad systems) and comfort/cushion systems, etc. (collectively "amenity systems").
The control valves of the present invention do not use the alternating current
electricity for actuation and may be inexpensive to produce.
In particular, the present invention requires no electricity at all for the cycling
action needed to alternately inflate and deflate the two channels of the bed or
seat pad. Of course, fluid supply (for example, air supply by the low pressure
air pump) must use some energy source, but this can be direct current which is
the only electrical source available in many applications. Even when applying in
a pad system where the AC electricity (e.g., 110 v, 60 hz) is readily available,
this invention may result in cost savings. The invention is therefore a simplification
of the present art and results in cost savings for the manufacturer and therefore
the consumer.
The present invention uses a piston which moves from one rest position to another
rest position within a casing when the pressure difference between a pressurizing
chamber and the other chamber reaches a predetermined level which overcomes the
attracting force of a holding magnet. When this movement of the piston occurs,
the channel that was previously being supplied fluid (e.g., air) now is allowed
to vent out slowly, and the channel that was previously venting now gradually fills
with fluid. Likewise, the cycle is repeated when the pressure difference in the
chambers reaches a predetermined level dictated by the magnetic force.
The piston is preferably held against a stop by the attractive force between
a magnet disposed adjacent the casing end and a soft-iron slug imbedded in the
piston. Conversely, a soft-iron slug may be disposed within the casing and a magnet
is imbedded in the piston. Alternatively, the soft iron in the piston may be omitted
in the case the piston is made of a magnet-attractive material. There are two such
magnets, one for each rest position.
Incoming fluid (e.g., air) is directed to one chamber of the invention or
the other depending on the position of the piston. Preferably, a passageway (e.g.,
two conduits in the piston) and the o-rings positioned around the piston facilitate
secured guiding of the operating fluid to the respective chamber which depends
on the position. The cycle time can be controlled by controlling the aperture through
which the incoming air must pass, and the release pressure is controlled by the
rest position air gap between the holding magnet and the soft-iron slug on the
piston. The cycle time can also be controlled by differentially pressurizing a
pressurizing chamber and venting the other chamber to predetermined rates, in which
switching of the piston occurs when the pressure differential overcomes the attracting
force of the one then holding magnetic member.
In accordance with a preferred embodiment of the invention, a fluid operated
control
valve for controlling fluid flow of a system which includes a first and a second
fluid channels therein, is disclosed. The control valve comprises: a hollow casing
with closed first and second ends; a piston member slidably disposed within the
casing and defining thereby within the casing a first chamber and a second chamber,
each chamber having a volume variable depending upon the position of the piston
member; a first magnetic member disposed adjacent the first casing end for attracting
the piston member to a first terminal position; and, a second magnetic member disposed
adjacent the second casing end for attracting the piston member to a second terminal
position. The control valve of the invention further comprises: an input port disposed
adjacent to an intermediate location in the casing for receiving operating fluid
thereto; a first output port disposed in the casing in fluid communication with
the first chamber; a second output port disposed in the casing in fluid communication
with the second chamber; and, a passageway for alternately guiding the operating
fluid from the input port to the first chamber and the second chamber depending
upon the position of the piston member within the casing, the position of the piston
being reciprocally moveable between the two terminal positions when the pressure
difference between a pressurizing chamber and the other chamber reaches a pressure
overcoming attracting force between the piston member and the one then-holding
magnetic member. The control valve of the invention preferably includes a first
vent port disposed between the input port and the first output port for venting
fluid therethrough, and a second vent port disposed between the input port and
the second output port for venting fluid therethrough.
In accordance with another preferred embodiment of the invention, an amenity
system
for use with a fluid source for providing operating fluid to the system, comprises:
an amenity member including a first and a second fluid channels therein, and a
control valve disposed in fluid communication with the fluid source and the fluid
channels of the amenity member and for alternately inflating and deflating the
fluid channels. The control valve of the invention includes: a hollow casing with
closed first and second ends; a piston member slidably disposed within the casing
and defining thereby within the casing a first chamber adjacent to the first end
of the casing and a second chamber adjacent to the second end of the casing, each
chamber having a volume variable depending upon the position of the piston member;
a first magnetic member disposed adjacent the first chamber for attracting the
piston member to a first terminal position; and, a second magnetic member disposed
adjacent the second chamber for attracting the piston member to a second terminal
position. The control valve of the invention further includes: an input port disposed
adjacent to an intermediate location in the casing for receiving the operating
fluid thereto from the fluid source; a first output port disposed in the first
chamber in fluid communication with the first chamber and the first fluid channel
of the amenity member; a second output port disposed in the second chamber in fluid
communication with the second chamber and the second fluid channel of the amenity
member; and a passageway for alternately guiding the operating fluid from the input
port to the first chamber and the second chamber depending upon the position of
the piston member within the casing, the position of the piston being reciprocally
moveable between the two terminal positions when the pressure difference between
a pressurizing chamber and the other chamber reaches a pressure overcoming attracting
force between the piston member and the one then-holding magnetic mating member,
thereby allowing alternate pressurizing of the fluid channels of the amenity member.
The control valve of the invention preferably includes a first vent port disposed
between the input port and the first output port for venting fluid therethrough,
and a second vent port disposed between the input port and the second output port
for venting fluid therethrough.
Other aspects, objects and features of the invention in addition to those mentioned
above will be understood from the following detailed description provided in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a side view of this invention in cross-section with the piston
at rest in its extreme left position.
FIG. 2 is a slice perpendicular to FIG. 1 through the left groove in
the piston, looking to the right.
FIG. 3 shows how this invention is employed in combination with an air pump
and a bed or seat pad.
FIG. 4 shows a side view of an alternative embodiment of this invention in cross-section
with the piston at rest in its extreme left position.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is described herein, particularly in conjunction with a
bed or seat pad system. However, the invention is not limited thereto and may be
applicable to various other systems including but without limitation to pad systems,
comfort systems, cushion systems, air supply systems, medical systems etc. (referred
collectively as "amenity systems") which include at least two fluid channels for
alternately pressurizing in accordance with the principles and concepts described herein-after.
FIG. 3 is a schematic representation illustrating how this invention is used
in conjunction with a utility pad system (e.g., a bed pad or seat pad system).
In order to produce the required pressure cycling to bed pad or seat pad
130,
the invention takes fluid (such as air, gas, liquid, etc.) from the source
110
and directs it alternately to channel
1a or channel
2a
as needed through fluid ports which will be described later in details. When
fluid is not being provided to a channel, the invention provides means for a slow
venting (emptying) of the fluid in that channel. Cycle time is controlled by adjustment
of the fluid flow rate from the source or the vent rate of then-venting channel,
for example by adjusting valve
120, etc. Maximum pressure in each channel
(or pressure difference of the two channels) is controlled with the magnet adjustment
screws
9 and
10 at each end of the control valve
100 of the invention.
Fluid control valve
100 of the invention consists basically of: a hollow
casing
3 with closed ends
4 and
5, at least three ports (i.e.,
input port
20, output ports
21 and
24), a piston
6
which slides left and right within the casing, and two adjustable magnets
7
and
8 positioned adjacent the casing ends
4 and
5. Adjustment
screws
9 and
10 are provided to adjust positioning of magnets
7
and
8. Soft-iron slugs
11 and
12 are provided to attract magnets
7 and
8, respectively. Conversely, the soft-iron slugs may be disposed
within the casing and the magnets be imbedded in the piston. Alternatively, the
soft iron in the piston may be omitted in the case the piston is made of a magnet-attractive
material such as steel.
O-rings
13,
14 and
15 are used to seal off the space
between the inside of the casing and the piston. The o-rings are of low durometer
and moveable along the piston
6 upon the reciprocal movement of the piston
within the casing
3. Preferably, they roll within the grooves provided instead
of sliding. This produces a tight seal with low resistance to left-right motion.
The end caps have protrusions on them which act as limits to the side-to-side motion
of the piston.
A passageway is provides for alternately guiding the air from the input port
to
chambers
1 and
2 depending upon the position of the piston
6.
For example, two fluid passageways (e.g., two circumferential grooves
16,
18 and two conduits
17,
19 respectively connected thereto)
are provided in the piston
6 so that for instance when incoming fluid enters
the right groove
16 as shown in FIG. 1, it passes through conduit
17
and is conducted into chamber
1. The left groove
18 is similarly
fitted with a conduit
19 which conducts air into the right chamber
2
when the piston has moved to the right against its limit. Alternatively, it is
also envisioned that various valve connections may be provide to accomplish the
fluid passageway. Also, the passageway may be disposed in the casing
3 in
association with a modified piston structure.
The magnet positions are adjusted so that they at most just touch the soft-iron
slugs imbedded in the piston. Backing a magnet out reduces the holding force exerted
by the magnet thereby reducing the air pressure required to break the piston loose
from its rest position. No special rotational positioning or clocking of the piston
in relation to the ports is required, and air is conducted into one of the grooves
and around the piston to the appropriate conduit regardless of clocking.
Operation of this invention is further described herein assuming the piston
is initially at rest against the left limit as depicted in FIG.
1. Fluid
entering at port
20 is confined between o-ring
14 and o-ring
15
and conducted into groove
16 and thence into conduit
17 and chamber
1. As fluid enters chamber
1, it proceeds to channel
1a
in the bed pad or seat pad
130 through port
21. Channel
1a
gradually fills with air. As the pressure in channel
1a increases,
the flow from chamber
1 to channel
1a subsides until a point
is reached where the pressure in channel
1a approximately equals
the pressure in chamber
1. As this pressure gradually rises, the total pressure
difference between chamber
1 and chamber
2I rises until this pressure
against the piston left wall exceeds the holding force of magnet
7. At this
point, the piston breaks free from magnet
7 and the air pressure in chamber
1 causes the piston to be pushed to the right until it comes to rest against
the right limit in chamber
2. When this is accomplished o-ring
13
will have rolled to the right of port
22, providing a small opening in the
system through which chamber
1 and channel
1a can vent. At
the same time o-ring
15 will have rolled to the right of port
23,
thereby sealing off chamber
2, and o-ring
14 will have rolled to
the right of port
20 causing air to be conducted into groove
18 and
then into chamber
2. Air is now conducted into channel
2a through
port
24 causing channel
2a to fill, repeating the entire process
with piston
6 now in its right-hand rest position.
In accordance with one aspect of the invention, the control valve
100
has
been designed so that the parts
3,
4,
5 and
6 can be
molded in plastic and assembled easily and inexpensively. End caps
4 and
5 are identical parts and are press fits onto the ends of casing
3
and the three o-rings
13,
14 and
15 are sufficiently soft
to accommodate small dimensional deviations in the fit of piston
6 within
the casing
3. There is no rotational sensitivity, and thus all parts can
be assembled without regard to the rotational orientation.
FIG. 4 illustrates an alternate embodiment of the invention which does not require
o-ring seals therein. In this embodiment, piston
25 is fitted to hollow
casing
3 with a minimum clearance (<0.001 in). This can be achieved
most easily by making casing
3 and piston
25 out of metal and machining
the parts to fit. Another way of accomplishing the required tight tolerances is
to mold the casing with an undersize inner diameter and the piston with an oversized
outer diameter and performing a final machining operation on the plastic parts
to achieve the required fit. For this embodiment, a dimensionally stable plastic
is essential. Without o-rings, the matching of the two parts is critical if the
fit is too tight, the friction is too high and if the fit is too loose, air leakage
will degrade performance by reducing the maximum achievable pressure in a channel.
Despite the difficulties described above, an aluminum working model was built and
tested with successful results using these principles.
Although the invention has been described and illustrated with respect to
the exemplary embodiments thereof, it should be understood by those skilled in
the art that various changes, omissions and additions may be made therein and thereto,
without departing from the spirit and scope of the present invention.
*
