Title: Valve arrangement and traffic calming device incorporating such an arrangement
Abstract: A reactive speed hump (2) includes a fluid flow control valve assembly (4). A first valve (18, 20, 21) is naturally open and a second valve (10, 14, 15, 16, 17), naturally closed. Application of fluid pressure on the control valve assembly below a first lower threshold level or above a second higher threshold level allows a flow of fluid from the inlet to the outlet, but an application of fluid pressure on the control valve between said first and second threshold levels allows substantially no fluid to flow between the inlet (7) and the outlet (9).
Patent Number: 7,004,193 Issued on 02/28/2006 to Heeks, et al.
| Inventors:
|
Heeks; Graham (Cheshire, GB);
Fox; Nigel Peter (Staffordshire, GB)
|
| Assignee:
|
Autospan Limited (Manchester, GB)
|
| Appl. No.:
|
782475 |
| Filed:
|
February 19, 2004 |
Foreign Application Priority Data
| Mar 12, 1997[GB] | 9705078 |
| Mar 12, 1998[GB] | PCT/GB98/00748 |
| Feb 25, 2000[GB] | 0004360 |
| Current U.S. Class: |
137/512.2; 137/517; 137/550 |
| Current Intern'l Class: |
F16K 17/04 (20060101) |
| Field of Search: |
137/4932,512.2,512.3,517,550,493.3,493.4,493.6,493.9
|
References Cited [Referenced By]
U.S. Patent Documents
| 120519 | Oct., 1871 | Hibberd.
| |
| 246858 | Sep., 1881 | Aitchison.
| |
| 637994 | Nov., 1899 | Klay.
| |
| 3152606 | Oct., 1964 | Vedder et al.
| |
| 3720181 | Mar., 1973 | Elkins.
| |
| 3971406 | Jul., 1976 | Inada et al.
| |
| 4068680 | Jan., 1978 | Sliger.
| |
| 4203685 | May., 1980 | Sanchez.
| |
| 4362424 | Dec., 1982 | Barber.
| |
| 4367975 | Jan., 1983 | Tyers.
| |
| 4534673 | Aug., 1985 | May.
| |
| 5415493 | May., 1995 | Eaton.
| |
| 5419652 | May., 1995 | Flanders.
| |
| 5586541 | Dec., 1996 | Tsai.
| |
| 6010277 | Jan., 2000 | Follman.
| |
| 6024510 | Feb., 2000 | Kamienchick.
| |
| 6241419 | Jun., 2001 | Bond.
| |
| 6276667 | Aug., 2001 | Arthur.
| |
| 6279247 | Aug., 2001 | Neitzel.
| |
| 6659682 | Dec., 2003 | Heeks.
| |
| 2002/0085881 | Jul., 2002 | Heeks.
| |
| 2003/0053860 | Mar., 2003 | Hall.
| |
| Foreign Patent Documents |
| 29 14 708 | Oct., 1980 | DE.
| |
| 3 447 712 | Aug., 1986 | DE.
| |
| 2 328 235 | Feb., 1999 | DE.
| |
| 0 370 154 | May., 1990 | EP.
| |
| 2 622 034 | Apr., 1989 | FR.
| |
| 2 699 567 | Jun., 1994 | FR.
| |
| 2 266 552 | Nov., 1993 | GB.
| |
| 2 288 419 | Oct., 1995 | GB.
| |
| 2 324 326 | Oct., 1998 | GB.
| |
| 2 328 235 | Feb., 1999 | GB.
| |
| 2 336 867 | Mar., 1999 | GB.
| |
| 0 020 924 | Apr., 2000 | KR.
| |
| WO 93/2470/7 | Dec., 1993 | WO.
| |
| WO 97/4676/0 | Dec., 1997 | WO.
| |
| WO 98/4056/3 | Sep., 1998 | WO.
| |
| WO 01/6305/1 | Aug., 2001 | WO.
| |
| WO 91/6305/1 | Aug., 2001 | WO.
| |
Primary Examiner: Hepperle; Stephen M.
Attorney, Agent or Firm: Woodcock Washburn LLP
Parent Case Text
This is a divisional of Ser. No. 10/204,895 filed Nov. 26, 2002, now U.S. Pat.
No. 6,726,399. This invention relates to valves and especially, but not exclusively,
to valves for use in reactive traffic calming humps, and to a traffic calming device
incorporating such a valve arrangement. This application as it applies to the designated
state US is a continuation-in-part of application Ser. No. 09/180,621 filed Jan.
8, 1999, (corresponding to PCT/GB98/00748) entitled Deformable Speed Hump, now
abandoned, the contents of which are hereby incorporated by reference.
Claims
What is claimed is:
1. An air flow control valve arrangement comprising at least a first and a second
valve, and a body for housing the first and second valves, the body defining an
air outlet, and an annularly-shaped air inlet having a diameter substantially smaller
than the air outlet so that the air inlet forms a jet, wherein the first valve
includes a first valve closure, movable against a first biasing means from its
natural open state to a closed state, and wherein the second valve includes a second
valve closure, movable against a second biasing means from its natural closed state
to its open state such that the application of air pressure on the control valve
assembly below a first lower threshold level or above a second higher threshold
level allows a flow of air through the valve arrangement but an application of
air pressure on the control valve between said first and second threshold levels
allows substantially no air to flow through the valve arrangement, said first valve
closure comprising a member having a shaft portion and a broad flat head portion
defining an annular sealing face connected to the shaft portion, the first valve
closure being located in an axial bore having an annular seat such that in the
closed position the head portion of the first valve closure sealably engages with
the annular seat, and wherein the second valve closure comprises a generally annular
member, the periphery of the generally annular member cooperating with the annular
seat of the first valve and which defines a central passageway incorporating the
first valve closure, the first valve closure being operative to open and close
the passageway.
2. An air flow control valve as described in claim 1 wherein said biasing means
are compression springs.
3. An air flow control valve as described in claim 1 wherein the body housing
is generally cylindrical with the air inlet and the air outlet being located at
opposite ends thereof.
4. An air flow control valve as described in claim 1 wherein a filter element
is located at the air outlet.
5. An air flow control valve as described in claim 1 wherein the first biasing
means is a compression spring positioned at least in part within the axial bore
and contacting the first and second valve closures.
6. An air flow control valve as described in claim 1 wherein the first valve
closure comprise a pair of locating legs that locate the first valve closure in
the axial bore by a snap fit.
7. An air flow control valve as described in claim 1 wherein the first valve
is movable from the open to the closed state in a first direction, and the annular
sealing face of the broad flat head portion is located in a plane substantially
perpendicular to the first direction.
8. An air flow control valve as described in claim 1 further comprising a retaining
disk mounted on an end of the body, wherein the second biasing means comprises
a spring located between the retaining disk and the second closure.
9. An air flow control valve as described in claim 1 wherein the first valve
is movable from the open to the closed state along a central axis of the body,
and the air line and the air outlet are located substantially along the central axis.
10. An air flow control valve arrangement comprising at least a first and a second
valve, wherein the first valve includes a first valve closure, movable against
a first biasing means from its natural open state to a closed state, and wherein
the second valve includes a second valve closure, movable against a second biasing
means from its natural closed state to its open state such that the application
of air pressure on the control valve assembly below a first lower threshold level
or above a second higher threshold lever allows a flow of air through the valve
arrangement but an application of air pressure on the control valve between said
first and second threshold levels allows substantially no air to flow through the
valve arrangement, said first valve closure comprising a member having a shaft
portion and a broad flat head portion defining an annular sealing face connected
to the shaft portion, the first valve closure being located in an axial bore having
an annular seat such that in the closed position the head portion of the first
valve closure sealably engages with the annular seat, the first valve closure comprising
a pair of locating legs that locate the first valve closure in the axial bore by
a snap fit, and wherein the second valve closure comprises a generally annular
member, the periphery of the generally annular member cooperating with the annular
seat of the first valve and which defines a central passageway incorporating the
first valve closure, the first valve closure being operative to open and close
the passageway.
Description
Hitherto, traffic calming humps (which are often colloquially referred
to as "sleeping policemen") have conventionally comprised rigid structures laid
across the road where calming is required. Typically, the humps are made, in situ,
of tarmac and are integrated into the road surface. Alternatively, although less
often, they comprise pre-fabricated structures made of, for example, steel which
are secured to the road by suitable fasteners. In any event, these conventional
humps have disadvantages. For example, they may present no less discomfort to occupants
of a vehicle travelling at an acceptably low speed (say up to 30 mph) than to those
of one travelling at an excessive speed. Also, they are potentially hazardous to
vehicles such as ambulances and fire engines which, in the case of an emergency,
might be travelling at a relatively high speed.
In order to overcome or mitigate those disadvantages, the use of "reactive" traffic
calming humps has been proposed. One type of reactive hump, with which the present
invention is especially concerned, is disclosed in UK patent application GB-A-2324326
and corresponding PCT application No WO 98/40563 and comprises a pre-fabricated
enclosure containing air and including a resiliently flexible, upper, hump-shaped
membrane. It operates on the principle that when, on the one hand, the wheels of,
for example, a car contact the membrane at a relatively low speed, the enclosure
will progressively deflate under the weight of the car thereby causing little discomfort
to the occupant(s). On the other hand, at excessive speeds, deflation is substantially
prevented and the membrane maintains its hump-shaped form, thereby jolting the
occupant(s) and inducing the driver to slow down prior to reaching the next hump.
Further, the hump should preferably provide a relatively smooth passage for emergency
vehicles, particularly ambulances, regardless of their speed of travel. The means
hitherto proposed to control deflation of such type of reactive hump have not been
entirely satisfactory. It is an object of the invention to provide valve means
adapted especially, but not exclusively, for permitting or substantially preventing,
as the case may be, deflation and collapse of a reactive traffic calming hump of
the type described above.
According to a first aspect of the present invention, there is provided
a reactive traffic calming device comprising a resiliently deformable enclosure
containing air, air within the enclosure communicating with the atmosphere via
a valve arrangement permitting the enclosure to be deflated under the weight of
a passing vehicle and to re-inflate after passage of the vehicle, said valve arrangement
comprising a pressure-sensitive valve adapted to remain open while the air within
the enclosure is up to a first pressure threshold, thereby permitting deflation,
and to close in response to pressure above said first pressure threshold, thereby
preventing deflation in response to excessive vehicle speed.
The pressure-sensitive valve may comprise a first valve closure biased into a
normally-open position and movable to a closed position, the air pressure within
the enclosure impinging on said first valve closure to overcome said biasing means
above said first pressure threshold.
The first valve closure may for example comprise a member having a shaft portion
mounted to slide within a bore, and a broader, head portion responding directly
to the air pressure. The biasing means may in this case comprise a coil spring
surrounding the shaft portion and acting against the head portion.
The valve arrangement may further comprise means defining a sensing chamber surrounding
the first valve closure, said inlet chamber communicating with the air within the
enclosure via a restricted air inlet. This provision isolates the closure from
transient air movements within the enclosure, promoting a more reliable response
and avoiding spurious and intermittent actuation of the valve.
The restricted inlet may be arranged so as to direct air in a jet directly at
the closure member. This feature may provide a more positive actuation of the valve.
The valve arrangement may further comprise a second valve, normally closed, arranged
so as to open and allow rapid deflation of the device in response to pressure exceeding
a second pressure threshold, greater than the first pressure threshold. This behaviour
permits the desirable response to emergency vehicles, which are characterised by
high weight and speed.
The second valve may comprise a second valve closure movable against second biasing
means from a normally closed position to an open position.
The first and second valves may be integrated in a single unit. One such embodiment
provides a fluid flow control valve comprising a body defining a fluid inlet and
a fluid outlet, the body housing, intermediate the fluid inlet and the fluid outlet,
first and second valves, the first valve including a first valve closure movable,
against a first biasing means, from a normally-open position to a closed position
and the second valve including a second valve closure movable, against a second
biasing means, from a normally-closed position to an open position, the arrangement
being such that, upon the application at the inlet of fluid pressure below a pre-determined
lower value, the first and second valves maintain their normally open and closed
positions respectively whereby fluid at the inlet can exhaust through the outlet
via said first valve, that upon the application at the inlet of fluid pressure
at or above said pre-determined lower value, but below a pre-determined higher
value, the fluid pressure causes the first valve closure to move to its closed
position while the second valve maintains its closed position whereby fluid is
prevented from flowing through the control valve, and that, upon the application
at the inlet of fluid pressure at or above said pre-determined higher value, the
fluid pressure causes the first valve closure to move to its closed position and
the second valve closure to move to its open position whereby fluid at the inlet
can exhaust through the outlet via the second valve.
The embodiment described therefore provides a pressure sensitive valve that will
respond in one or other of three different ways depending upon the increased fluid
pressure applied to its inlet. In the context of a reactive road hump of the type
described above, the valve functions as follows.
In a first case, when the wheels of a vehicle, such as a car, surmount the hump,
the air in the enclosure will increase in pressure. Provided, however, that the
vehicle is travelling at, or less than a pre-determined "safe" speed, the pressure
increase in the enclosure, and therefore at the inlet of the control valve, will
be limited and insufficient to cause the first valve to close, as air will be able
to exhaust from the enclosure via the first valve and the outlet of the control
valve. The flexible membrane therefore progressively collapses and the vehicle's
occupant(s) will experience little or no discomfort.
In an alternative case, if the vehicle is travelling at a speed in excess of
the
pre-determined safe speed, the sudden pressure increase will be sufficient to cause
the first valve to close, but will generally be insufficient to cause the second
valve to open. Exhaust of air from the enclosure will therefore be substantially
prevented and so the hump will more or less maintain its normal form and the occupant(s)
will experience a discomforting jolt, thus inducing the driver to slow down.
Further, in the case of, for example, heavy emergency vehicles, the pressure
increase will, more or less regardless of speed, be sufficiently high to cause
the first valve to close and the second valve to open, whereupon air can exhaust
from the enclosure and the flexible membrane will collapse and little or no discomfort
will be experienced.
In a preferred, very compact, embodiment of a fluid flow control valve of the
invention, the first valve closure comprises a generally annular member, the periphery
of which co-operates with an annular seat of the first valve, and which defines
a central passageway incorporating the second valve closure, the latter being operative
to open or close the passageway as the case may be. Especially in that embodiment,
the body is preferably generally cylindrical with the fluid inlet and fluid outlet
being located at opposite ends thereof.
The biasing means may for example be compression springs, such as helical coil
springs. Of course, other forms of spring may be suitable.
As will be appreciated, the reactivity of the hump may be varied as desired by
varying the closing and opening characteristics of the first and second valves,
as is described in more detail below. This may be by selection of the spring or
other biasing means, by adjustments of geometry, or selection of parts of different geometry.
The invention further provides a valve arrangement for use in a reactive traffic
calming device of the type described incorporating, first and optionally second
fluid flow control valves adapted to operate as defined above. The valves may be
arranged to be located separately in the wall but preferably they are integrated
into a unitary body as defined by the first aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
A fluid flow control valve constructed in accordance with the first aspect of
the
invention, and a reactive traffic calming hump incorporating it, will now be described
in more detail, by way of example only, with reference to the accompanying drawings
in which:
FIG. 1 is a side elevation, on a reduced scale, of the reactive traffic calming
hump; and
FIG. 2 is a sectional side elevation, on a scale of about 3:1, of the control valve.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Referring first to FIG. 1, the reactive traffic calming hump, which is
generally of the form shown in FIG. 6 of GB-A-2324326, includes a relatively rigid
base
1 having peripheral portions
1a,
1b through
which suitable fasteners (not shown) may be inserted in order to secure the hump
to a road surface. A resilient, relatively flexible upper membrane
2 and
opposed side walls, only one of which
3 can be seen, are secured to the
base
1. The base, membrane and side walls form an enclosure containing air
at atmospheric pressure. The enclosure is completely sealed but is provided with
the control valve shown in FIG. 2 which is securely located in an aperture
4
formed in the side wall
3. Usually, a complete traffic calming hump will
comprise a number of modules as described above arranged in side-by-side relationship
across the road where calming is required.
Referring now to FIG. 2, the control valve comprises a generally cylindrical
hollow body
5 housing various valve components as described below. The body
5, which may for example be a plastics moulding, is formed with an annular
locating flange
6 which, when the control valve is in position, abuts the
external surface of the side wall
3 of the hump with the body
5 extending
into the interior of the hump.
The innermost end of the body
5 defines, internally of the enclosure,
an air inlet
7, while a retaining disc
8 engaged with the body
5
at its outermost end, for example by means of a bayonet fixture, defines an air
outlet
9. The flow of air between the inlet
7 and the outlet
9
is selectively controlled, in dependence upon the air pressure prevailing at the
inlet
7, by two valves housed in the body
5. One valve ("the second
valve") comprises an annular seat
10 formed integrally with the body
5
and a closure
11. The closure
11, which also may be a plastics moulding,
comprises a main portion
12 having an axial, stepped bore
13 formed
in it, an annular flange
14 and a plurality of spaced, radially resilient
locating legs having enlarged ends, two of which are shown and designated
15
and
16. The closure
11, and more particularly the flange
14
thereof, is normally urged into sealing contact with the annular seat
10
by a relatively strong compression spring
17 sandwiched between the flange
14 and the retaining disc
8. As will be apparent, the closure
11
is located by its legs
15 and
16 etc in the body
5 as a snap fit.
The other valve ("the first valve") comprises an annular seat
18 defined
by an end face of the closure
11 and which surrounds one end of the bore
13, and a closure
19. The closure
19, which likewise may be
a plastics moulding, comprises a head
20 from which extend a plurality of
spaced, radially resilient locating legs having enlarged ends, two of which are
shown and designated
21 and
22. The closure
19 is located
by its legs
21,
22 etc in the axial bore
13 as a snap fit.
The head
20 defines an annular sealing face
21 which is normally
urged into a position spaced from the seat
18 by means of a relatively light
compression spring
23.
Normally, therefore, the second valve is in a closed position, whereas
the first valve is in an open position. The two valves react in one of the following
three ways when a vehicle surmounts the flexible membrane
2 of the hump.
1. If the vehicle is travelling at a relatively low, "safe", speed, the
air pressure in the enclosure will tend to increase, but at such a rate that air
in the enclosure will simply exhaust from the outlet 9 via the inlet 7
and the open first valve and more particularly via the bore 13 and the slotted
closure 19. In other words, the pressure will not rise to a value sufficient
for the force exerted on the head 20 to overcome that provided by the spring
23, whereby the first valve remains open (the second valve will, of course,
remain closed). Accordingly, the membrane 2 will progressively collapse
and little or no discomfort will be experienced by the vehicle's occupant(s). Once
the vehicle wheels are clear of the hump, the membrane 2 will resile back
to its normal, raised position, air simultaneously being drawn into the enclosure
via the open, first valve.
It will be appreciated that the operation of the first valve, ie. the conditions
under which it remains open or closes may be varied by varying the available cross-sectional
flow area through it, the cross-sectional area of the head
20 and/or the
properties of the compression spring
23. By way of example, these may be
selected such that the first valve will remain open for so long as the pressure
at the inlet
7 is at or below about 0.3 bar gauge.
2. If the vehicle is travelling at a higher, "unsafe", speed, there will
be a sudden increase in the air pressure in the enclosure sufficient to close the
first valve, the closure 19 moving axially in the bore 13, against
the spring 23, until the surface 21 sealingly engages the seat 18.
However, the second valve will remain closed. Accordingly, in that situation the
control valve acts as a check valve and little or no exhaust of air will be possible
from the enclosure. The hump will, therefore, substantially maintain its normal
form and impart a discomforting jolt to the vehicle's occupant(s), thus inducing
the driver to slow down. Once the vehicle wheels are clear of the hump, the first
valve will revert to its normal, open, position.
3. If the vehicle is heavy (such as an emergency vehicle), there will be
a sudden increase in pressure, more or less regardless of the speed of the vehicle,
to such a value that not only will the first valve close as described in 2 above,
but also the force exerted on the closure 11 by the fluid pressure will
be sufficiently high to overcome the force exerted on it by the compression spring
17. The closure 19, and more particularly the flange 14, will
therefore move out of sealing contact with the seat 10 thus allowing air
in the enclosure to exhaust from the outlet 9 via the inlet 7 and
the spaces between the legs 15 and 16, whereby the hump collapses
as the vehicle's wheels pass over it. Subsequently, the second and first valves
and the hump will resile back to their normal positions.
The pressure at which the second valve opens may be varied by altering the effective
cross-sectional area of the closure
11 (ie. the area of it acted upon by
the fluid) and the properties of the spring
17. As an example, these may
be selected such that it will not open at a pressure below about 3 bar gauge.
In FIG. 2, the dashed lines illustrate two desirable modifications to the valve.
More particularly, the valve may be protected against the ingress of foreign matter
through the outlet
9 by a filter element
24 retained by the body
5. Filter element
24 may of course comprise a wire or plastic mesh.
For best protection against ingress of dirt and moisture, however, the filter element
in this example comprises a waterproof, air-permeable (so-called "breathable")
membrane such as that sold under the trade marks SYMPATEX or GORE-TEX. The valve
may be serviceable by removal of this element
24, using a tool adapted to
extract the valve mechanism. Alternatively, for maximum security, the valve unit
may be inaccessible except by removal of the hump from the road. According to a
preferred embodiment, subject of co-pending application GB 0103501.3, the device
may be mounted on a concrete slab, removable bodily from the road.
A second modification shown dotted in FIG. 2 is that and the inlet
7 may
comprise a jet
7′ defined by an annular member
25 secured
to the body
5. The jet
7′, because of its restricted diameter,
serves to increase the velocity of incoming air, whereby the response of the valve
is improved. The member
25 also defines a sensing chamber substantially
isolated from the main interior space of the device, which protects the valve from
spurious actuation, as air moves from one part of the deformable enclosure to another.
This benefit can be obtained by providing a restricted inlet
7 to the sensing
chamber, without necessarily creating a jet
7′ directed at the head
20 of the closure.
As noted above, a valve of the invention may comprise largely plastics mouldings,
but of course any other suitable materials may be used.
Further, while a control valve of the invention is especially suitable for
use with reactive traffic calming humps, it may have alternative applications where
valve open/check/valve open functions are required depending on the magnitude of
the fluid pressure prevailing at the inlet.
*
