U.S. patent application number 11/791059 was filed with the patent office on 2008-07-17 for rodent entry prevention device.
Invention is credited to Christian Thiim.
Application Number | 20080168720 11/791059 |
Document ID | / |
Family ID | 35550651 |
Filed Date | 2008-07-17 |
United States Patent
Application |
20080168720 |
Kind Code |
A1 |
Thiim; Christian |
July 17, 2008 |
Rodent Entry Prevention Device
Abstract
The present invention relates to a device (1) for preventing
entry of a rodent through a pipe comprising a jacket (2), a first
gate plate (3) and a locking device (4), where the jacket (2) is
adapted for mounting in the discharge pipe, where the first gate
plate (3) is pivotally arranged inside the jacket (2), and where
the locking device (4) is arranged in connection to the first gate
plate (3), wherein a second gate plate (6) is pivotally arranged at
a distance (X) from the first gate plate (3) inside the jacket (2)
and connected to the first gate plate (3) by means of a connection
assembly (8).
Inventors: |
Thiim; Christian; (Herning,
DK) |
Correspondence
Address: |
JAMES C. WRAY
1493 CHAIN BRIDGE ROAD, SUITE 300
MCLEAN
VA
22101
US
|
Family ID: |
35550651 |
Appl. No.: |
11/791059 |
Filed: |
November 17, 2005 |
PCT Filed: |
November 17, 2005 |
PCT NO: |
PCT/DK05/00732 |
371 Date: |
August 17, 2007 |
Current U.S.
Class: |
52/101 |
Current CPC
Class: |
E03F 7/06 20130101 |
Class at
Publication: |
52/101 |
International
Class: |
E03F 7/06 20060101
E03F007/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 18, 2004 |
DK |
PA 2004 01794 |
Claims
1. Device (1) for preventing entry of a rodent into a building
through a pipe comprising a jacket (2), a first gate plate (3) and
a locking device (4), where the jacket (2) is adapted for mounting
in the discharge pipe, where the first gate plate (3) is pivotally
arranged inside the jacket (2), and where the locking device (4) is
arranged in connection to the first gate plate (3), wherein said
jacket has a shape substantially corresponding to the inner shape
of the pipe and an extend covering more than half of the
circumference of said pipe, and that a second gate plate (6) is
pivotally arranged at a distance (X) from the first gate plate (3),
inside the jacket (2) and in communication with the first gate
plate (3) by means of a connection assembly (8).
2. Device (1) according to claim 1, wherein the connection assembly
(8) comprises a push rod (9) and a guidance pipe (10), where the
push rod (9) is pivotally connected to the second gate plate (6),
and where the guidance pipe (10) is arranged on part of the push
rod (9), and where the first gate plate (3) is provided with an
aperture (19) adapted to interact with the push rod (9).
3. Device (1) according to claim 1, wherein the locking device (4)
comprises a locking clamp (11) and a pivotal detent (12), the
locking clamp (11) being connected to the first gate plate (3) and
the detent (12) being pivotally connected to the jacket (2).
4. Device (20) according to claim 1, wherein the connection
assembly (21) comprises a first tension rod (22) and the locking
device (23) comprises a hook member (24) and a locking pin (25),
and where the first tension rod (22) is pivotally connected to the
second gate plate (6), and where the hook member (24) is pivotally
arranged inside the jacket (2) and pivotally connected to the first
tension rod (22), and where the locking pin (25) is connected to
the first gate plate (3).
5. Device (30) according to claim 1, wherein the connection
assembly (31) comprises a second tension rod (32), a guidance tube
(33), a guidance strap (34) and the locking device (35) comprises a
locking pin (36), where the second tension rod (32) is pivotally
connected to the second gate plate (6) and connected to the
guidance strap (34), which is arranged inside the jacket (2)
between the first and second gate plates (3, 6), and where the
locking pin (36) is connected to the first gate plate (3).
6. Device (1) according to claim 1, wherein the distance (X)
between the first gate plate (3) and the second gate plate (6) is
minimum 30 mm, preferably more than 50 mm.
7. Device (1) according to claim 1, wherein the jacket (2) is
provided with a number of projections (17) arranged on an outer
surface of the jacket (2).
8. Device according to claim 1, wherein the connection assembly
comprises a first notch (40) arranged on the second gate plate (6)
and a pivotal pendulum member (41) adjacent the first gate plate
(3) on the opposite side of said first gate plate (3) to the second
gate plate (6), and that an aperture (42) is provided in the first
gate plate (3) through which aperture (42) the pendulum member (41)
may engage the first notch (40).
9. Device according to claim 8, wherein the first and second gate
plates (3,6) extend above the shafts (5,7) about which they pivot,
and that the sections of the gate plates (3,6) extending above the
shafts (5,7) are angled against the flow direction in relation to
the plane of the gate plates.
10. Device according to claim 8, wherein the pendulum member in its
rest position partly projects through the aperture, and an
engagement edge of the pendulum member engages an edge of the
aperture in the first gate member, and when the first notch is
brought into contact with the pendulum member, the pendulum member
is released from its engagement with the first member such that the
first gate may pivot.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a device for preventing
entry of a rodent through a pipe comprising a jacket, a first gate
plate and a locking device, where the jacket is adapted for
mounting in the discharge pipe, where the first gate plate is
pivotally arranged inside the jacket, and where the locking device
is arranged in connection to the first gate plate.
BACKGROUND OF THE INVENTION
[0002] Through time rodents have tried and succeeded in invading
the human habitation, as the survival instinct of the rodents makes
them e.g. seek for food or better living conditions during cold
seasons or famines.
[0003] In developed areas e.g. cities with sewage systems, rodents
and especially rats are a major problem, because they breed fast,
spread hazardous human diseases, and destroy building constructions
as they nest or invade a building.
[0004] It is a fact that every major city has a growing population
of rats, which typically live and breed in the cities sewage
systems. Due to occasional flooding of the sewage pipes, cold
periods or famines, the rats try to invade buildings in order to
find better living conditions.
[0005] If a building is invaded by rodents e.g. rats, several means
are provided for killing the rats, e.g. different kinds of poison
and different kinds of mechanic and/or lethal traps. The
disadvantages of the aforementioned means are that when using e.g.
poisons the rats sometimes die in unknown places of a building
causing severe odour nuisances. Furthermore, rats killed by poison
can represent a health risk for a carnivore eating the rats,
meaning that pet animals, like dogs and cats, are exposed, thus
trapped or killed rats have to be disposed of.
[0006] To avoid these disadvantages and the costs of procurement of
the aforementioned means, it is obvious to prevent the rodents e.g.
rats from entering the buildings through pipe installations.
[0007] Different kinds of rodent entry prevention devices have been
provided and adapted for arrangement in the pipe installations,
e.g. grates, tilting gate, water traps, one-way-valves and
others.
[0008] Everyone of these rodent entry prevention devices prevent a
number of rodents from invading a building, however studies of rats
have shown that the animals are very persistent and inventive and
try to circumvent the device. As the rats are quick learners, they
often succeed in doing so hence the usefulness of the device is
significantly reduced.
[0009] Furthermore, another disadvantage of such devices is that
they do not allow unimpeded flow through the pipe installation.
Thus the risk of clogging the pipe installation increases, and
since the rats can swim, a water trap does not provide an efficient
barrier to rats.
OBJECT OF THE INVENTION
[0010] Thus an object of the present invention is to provide a
rodent entry prevention device, which significantly reduces the
risk of rodents, especially rats, invading a building through any
pipe installation and which at the same time allows unimpeded flow
of water through the pipe installation.
[0011] This is achieved with a device according to claim 1, wherein
a second gate plate is pivotally arranged at a distance from the
first gate plate inside the jacket and which is connected to the
first gate plate by means of a connection assembly.
DESCRIPTION OF THE INVENTION
[0012] To obtain a device which is sure to prevent a rodent from
entering a building through a pipe, the device according to the
present invention comprises a jacket, wherein a first gate plate
and a second gate plate is pivotally arranged at a distance and
functionally connected by means of a connection assembly, and where
a locking device is arranged in connection to the first gate
plate.
[0013] The two-gate-plate-design of the device makes is superior to
the design of any other device, as other devices are provided with
only one gate. Due to the distance between the two gate plates and
the locking device being connected to the first gate plate and the
functional connection, which is ensured by the connection assembly,
the rat cannot open both gate plates at the same time meaning that
the rat cannot circumvent the device in any other ways than by
destroying the device or the pipe.
[0014] It is universally known that rats can and will eat/bite
their way through e.g. cement, plastic material, wood or the like,
if they are sure to find food, soil, heat or arid conditions on the
other side of the material. Thus in order to prevent or reduce the
risk of rats biting/chewing and subsequently destroying the gate
plates, the device is made of a very hard material, e.g. stainless
steel or reinforced plastic material, which provides another
advantage, as these materials withstand the aggressive environment,
which is typical of sewage/drain systems.
[0015] According to an embodiment of the present invention the
connection assembly comprises a push rod and a guidance pipe, where
the push rod is pivotally connected to the second gate plate and
where the guidance pipe is arranged on a part of the push rod, and
where the first gate plate is provided with an aperture which is
adapted to interact with the push rod.
[0016] The push rod is longer than the distance between the two
gate plates and is at one end hinged to the second gate plate and
the other end is arranged through the aperture in the first gate
plate, thus it is possible to swing the two pivotally hinged gate
plates.
[0017] In order to guide the push rod and to make the two gate
plates co-operate, the push rod is arranged coaxially inside the
guidance pipe, which is slideably mounted along a part of the push
rod.
[0018] The guidance pipe is either slightly shorter or equal to the
distance between the two gate plates, whereby any allowable
movement of one gate plate results in a subsequent quick movement
of the other gate plate.
[0019] To prevent rats from manipulating the first gate plate and
from opening the gate plate in the direction of the water flow, the
locking device comprises a locking clamp and a pivotal detent, the
locking clamp being connected to the first gate plate and the
detent being pivotally connected to the jacket.
[0020] The locking device does not allow any opening of the gate
plates even if the rat succeeds in manipulating the first gate
plate in either direction, as the pivotal detent is engaged with
the locking clamp. Only in case of full water flow, the push rod
disengages the pivotal detent from the locking clamp making it
possible to open both gate plates. Likewise when the water flow
falls, the pressure on the second gate plate decreases and the push
rod pulls back making the pivotal detent swing back and engage with
the locking clamp.
[0021] According to another embodiment of the present invention the
connection assembly comprises a first tension rod, and the locking
device comprises a hook member and a locking pin, where the first
tension rod is pivotally connected to the second gate plate, and
where the hook member is pivotally arranged inside the jacket and
pivotally connected to the first tension rod, and where the locking
pin is connected to the first gate plate.
[0022] The first tension rod is at one end pivotally hinged to the
second gate plate at a point higher than the shaft, whereupon the
second gate plate and at the other end is pivotally hinged to the
hook member below the point where it is pivotally hinged to the
jacket. In the light of the above any movement of the second gate
plate due to the water flow rising or falling results in the hook
member disengaging from the locking pin on the first gate plate,
whereby the water flow opens the first gate member and subsequently
allows full flow through the device.
[0023] A rat trying to open the first gate plate in the direction
of the water flow will not succeed, because the hook does not allow
the locking pin to rotate clockwise around the shaft whereupon the
first gate plate is pivotally hinged.
[0024] A rat trying to push the first gate plate open in the
opposite direction of the water flow probably does not succeed, as
the hook member engages the locking pin and hence prevents the
opening of the first gate plate, which is pivotally hinged. If the
rat contrary to expectations opens the first gate plate, it is
detained when it reaches the second gate plate as there is no room
for the second gate plate to open in the direction of the water
flow.
[0025] According to another embodiment of the present invention the
connection assembly comprises a second tension rod, a guidance tube
and a guidance strap. The locking device comprises a locking pin,
where the second tension rod is pivotally connected to the second
gate plate and connected to the guidance strap, which is arranged
inside the jacket between the first and the second gate plates, and
where the locking pin is connected to the first gate plate.
[0026] The second tension rod is at one end pivotally hinged to the
second gate plate at a point higher than the shaft whereupon the
second gate plate is supported by the guidance strap, which is
connected to the jacket. This means that any movement of the second
gate plate due to the water flow rising or falling causes the
second tension rod to disengage from the locking pin on the first
gate plate, whereby the water flow may open the first gate member
and allow fill flow through the device. A rat trying to open the
first gate plate in the direction of the water flow will not
succeed, because the second tension rod does not allow the locking
pin to rotate clockwise around the shaft whereupon the first gate
plate is pivotally hinged.
[0027] A rat trying to push the first gate plate open in the
opposite direction of the water flow is detained when it reaches
the second gate plate, because the second gate plate cannot open in
the opposite direction of the water flow, because of the guidance
tube being arranged on the second tension rod between the guidance
strap and the second gate plate, whereby any pushing on the second
gate plate results in the guidance tube being pushed against the
guidance strap, which prevents the second gate plate from
opening.
[0028] The rat will not succeed in opening the second gate plate in
the opposite direction of the water flow, because there is no room
for the second gate plate to open in the direction of the water
flow, when the first gate plate is open in the opposite direction
of the water flow.
[0029] In order to prevent a rat from pushing the first gate plate
and then manage to open both gate plates in the opposite direction
of the water flow thereby allowing free passage, a covering plate
is arranged inside the jacket. This covering plate is positioned in
the direction of the water flow just behind the second gate plate.
The dimension of the covering plate allows the plate to protrude
into the jacket. It is important that a bent portion of the
covering plate has a possible contact point on the second gate
plate, which is lower than the shaft whereupon the second gate
plate is pivotally hinged. The covering plate can also be closely
arranged with the second gate plate when in closed position.
[0030] In this case the covering plate prevents the second gate
plate from being pivoted in the opposite direction of the water
flow, and because the first gate plate is connected to the second
gate plate either directly or through the locking device, the
covering plate furthermore prevents the first gate plate from
pivoting in the opposite direction of the water flow.
[0031] One reason why the device according to the present invention
is very efficient against prying rats is that the distance between
the first gate plate and the second gate plate is minimum 30 mm,
preferably more than 50 mm. The distance between the two gate
plates ensures that rats cannot circumvent the first gate plate and
then activate the second gate plate, as the rats cannot reach the
second gate from the first gate in any way.
[0032] Furthermore, if a small rat succeeds in opening the first
gate plate it will be trapped between the two gate plates, however,
because of the device construction the rat can escape the same way
as it entered the device.
[0033] The device is typically installed in e.g. a sewage/drain
pipe of a building and the device must be able to allow unimpeded
flow through the pipe when the gate plates are in open position.
Likewise the device must allow a certain flow through the pipe when
the gate plates are in closed position, which reduces the risk of
clogging the pipe. If effluent is flowing through the device when
the gate plates are in closed position, the risk of clogging the
device is significantly reduced when the first gate plate
preferably is smaller than the second gate plate.
[0034] This reason for this is that effluent passing through the
second gate plate easily passes through the smaller first gate
plate, whereby the risk of effluent being detained between the gate
plate is reduced along with the risk of the device being prevented
from functioning properly e.g. by preventing opening of the gate
plates in case of full flow through the pipe.
[0035] The gate plates have either a circular or polygonal
dimension, however, they are always of a dimension smaller than the
pipe in which they are supposed to be installed thus they secure
free passage between the jacket/pipe and the gate plates and never
block the pipe.
[0036] The device according to the present invention is intended
for both new and old pipe installations. In new installation the
device can be positioned anywhere, whereas in old installations the
device is typically positioned in pipe discharges e.g. in a central
drain shaft. In order to maintain or exchange a device it is
important that the device is correctly arranged in the pipe, e.g.
it must not be pushed too far up the pipe. To avoid this, the
jacket is provided with a number of projections, which are arranged
on an outer surface of the jacket. These projections engage with
the rim of the pipe end section preventing the device from being
pushed too far up the pipe. The projections can be a number of
protrusions spaced around the outer surface of the jacket or an
encircling collar, which is integrated with the outer surface of
the jacket.
[0037] In a further advantageous embodiment of the invention, a
different mechanism foresees the interlocking of the two gate
plates in relation to each other such that entrance in one
direction is impossible. In this embodiment, the connection
assembly comprises a first notch arranged on the second gate plate
and a pivotal pendulum member adjacent the first gate plate on the
opposite side of said first gate plate to the second gate plate,
and that an aperture is provided in the first gate plate through
which aperture the pendulum member may engage the first notch. The
pendulum assures that the first gate plate in its rest position,
i.e. in its position where the plane of the gate is perpendicular
to the longitudinal axis of the pipe in which it is mounted, is
engaged in the aperture provided in the first gate member such that
the first gate member cannot pivot in any direction. Therefore, if
a rodent attempts to enter in the direction indicated by the arrow
"B", it will not be able to move the first gate member in any
direction. When waste water, however, is led towards the device,
the second gate member will pivot due to the water pressure whereby
the first notch attached to the second gate member will engage the
pendulum member, and release the engagement between the pendulum
member and the first gate member such that also the first gate
member may pivot and thereby allow the waste water to pass through
the pipe.
[0038] These and other aspects are illustrated in the further
dependent claims to this particular embodiment.
[0039] To easily mount or dismount the device from a pipe, the
jacket is provided with a number of mounting holes, which are
adapted to engage with protrusions of a tool. When the tool
protrusions are engaged in the mounting holes, it is possible to
reduce the diameter of the jacket slightly, making it possible to
slide the device into a pipe or pull the device out of a pipe.
[0040] The device can be used at the entrance of each building pipe
installation, thus securing a building against rat invasion.
Alternatively, one device can be used in a central drain shaft
isolating an entire section of a sewage system, which section
covers all entrances to a building, all entrances to a number of
buildings or the pipe string for an entire street.
[0041] The device can be used in pipes having an inclination up to
45 degree from horizontal, as the gate plates are pivotally hinged.
In most piping installation this is sufficient.
[0042] The device according to the present invention is described
for preventing rats from invading a building through a pipe.
However, the device may be used to prevent other kinds of rodents
from entering building constructions, bridges, towers, ships,
vehicles or planes.
SHORT DESCRIPTION OF THE DRAWINGS
[0043] The invention is described in more detail below with
reference to the accompanying drawing in which:
[0044] FIG. 1 shows a side view of a first embodiment of a device
according to the present invention,
[0045] FIG. 2 shows a side view of an open device according to the
present invention,
[0046] FIG. 3 shows a perspective view of the device in FIG. 1.
[0047] FIG. 4 shows a side view of another embodiment of a device
according to the present invention, and
[0048] FIG. 5 shows a side view of a further embodiment of a device
according to the present invention.
[0049] FIG. 6 shows a side view of a further embodiment.
[0050] FIG. 7 shows a plane view of the first gate plate 3.
DETAILED DESCRIPTION OF THE INVENTION
[0051] FIG. 1 shows a device 1 for preventing entry of a rodent
(not shown) through a pipe 37 comprising a jacket 2, a first gate
plate 3 and a locking device 4, where the jacket 2 is adapted for
mounting in the pipe 37, where both the first gate plate 3, which
is pivotally hinged around shaft the 5, and the second gate plate
6, which is pivotally hinged around the shaft 7, is arranged inside
the jacket 2 with a mutual distance X.
[0052] The two gate plates 3, 6 are functionally connected by means
of a connection assembly 8 comprising a push rod 9 and a guidance
pipe 10, where the push rod 9 at one end is pivotally hinged to the
second gate plate 6, and where the guidance pipe 10 is arranged
around the part of the push rod 9, which is positioned between the
two gate plates 3, 6.
[0053] The length of the push rod 9 exceeds the distance X, causing
one end to interact with an aperture (not shown) in the first gate
plate 3. The length of the guidance pipe 10 is slightly shorter
than the distance X, whereby any movement of either gate plates 3,
6 causes movement of the other gate plate 3, 6.
[0054] The guidance pipe 10 may be hinged to the first gate plate
3, such that the different parts of the device all are fastened in
one way or the other into one unit, meaning that there are not any
loose parts.
[0055] The locking device 4 comprises a locking clamp 11 and a
pivotal detent 12, where the locking clamp 11 is connected to the
first gate plate 3 and the detent 12 is pivotally hinged around
shaft 13 to the jacket 2, and when the two gate plates 3, 6 are in
locked position, the detent 12 engages with the locking clamp 11,
which prevents the two gates 3, 6 from being opened in the
direction A.
[0056] The shaft 5 is positioned higher than the shaft 7 and in
addition to the second gate plate, which is larger than the first
gate plate 3. This results in that the second gate plate 6, in a
open position, is positioned lower than the first gate plate 3, in
open position, and the gate plates overlap each other, thus
protecting the aperture (not shown) in the first gate plate 3 and
prevents the connection assembly 8 from being filled with
effluent.
[0057] Furthermore, it is possible to see that the distances
between B and C to the bottom of the pipe 37 are different, thus
clogging is prevented as the distance between B and the pipe is
smaller than the distance between C and the pipe, hence effluent
(not shown) which passes below the second gate plate 6 can surely
pass below the first gate plate 3 too.
[0058] The covering plate 14 is arranged inside the jacket 2 just
behind the second gate plate 6 and is shown with a bended portion
15, which has a possible contact point 16 below the shaft 7,
whereupon the second gate plate 6 is pivotally hinged. This
prevents the second gate plate 6 from being openable in the
opposite direction A. Furthermore, the first gate plate 3 is
prevented from being opened in the opposite direction A due to the
guidance pipe 10.
[0059] As illustrated the jacket 2 extends outside the pipe 37, for
example into a manhole opening. The jacket 2 insertion into the
pipe is limited by the projections 17 which leave a bit of the
jacket 2 accessible. This is important in that it makes it
relatively easy to remove the device 1 when necessary.
[0060] It should further be noted that the jacket 2 has a shape
substantially corresponding to the inner shape of the pipe 37. The
jacket 2 has an extend, which is slightly larger than the inner
periphery of the pipe 37, such that the device 1 due to the
inherent stresses in the jacket 2 will be held by the friction
between the pipe 37 and the jacket. Due to the jacket covering more
than half of the inner circumference of the pipe 37 it will be
firmly held in place.
[0061] FIG. 2 shows the device 1 having both the first gate plate 3
and the second gate plate 6 in open position in the direction A.
Due to the pressure of full flow on the second gate plate 6, the
push rod 9 has disengaged the detent 12 from the locking clamp 11
and the guidance pipe 10 ensures a nearly simultaneous opening of
the first gate plate 3.
[0062] FIG. 3 shows a device 1, from which it is possible to see
that the jacket 2 is not a tube but a semicircle, and the jacket 2
is provided with projections 17 and mounting holes 18 at the end of
the jacket 2, which is closest to the first gate plate 3. The
projections 17 prevent the device 1 from being pushed too far up a
pipe (see FIG. 1) and the mounting holes 18 are used for easy
installation of the device 1 in a pipe (nor shown) with a special
tool (not shown).
[0063] The first gate plate 3 is provided with an aperture 19,
which interacts with the push rod 9, whereby it is possible to
pivot the gate plates 3, 6 to an almost horizontal position without
disengaging the push rod 9 from the aperture 19.
[0064] In FIGS. 2, 4 and 5 only the mechanisms relating to the
functioning of the gates are illustrated. It should in this context
be noted that all the embodiments described may be fitted inside a
jacket as illustrated in FIG. 1 or FIG. 3. Alternatively, the gates
and mechanisms may be installed directly into the walls of the
pipe. Care should be taken with these embodiments in that flushing,
cleaning and the like may only be carried out from one side
indicated by the arrow A as it is not possible to remove the gates
as these are integral parts of the pipe.
[0065] FIG. 4 shows a device 20 with gate plates 3, 6, where the
connection assembly 21 comprises a first tension rod 22, and the
locking device 23 comprises a hook member 24 and a locking pin
25.
[0066] The first tension rod 22 is pivotally hinged around the
shaft 26 to the second gate plate 6, and the hook member 24 is
pivotally arranged around the shaft 27 to the jacket 2 and
pivotally hinged to the first tension rod 11, and the locking pin
25 is connected to the first gate plate 3.
[0067] An opening of the second gate plate 6 in the direction A
causes the first tension rod 22 to be displaced and disengage hook
member 24 from the locking pin 25 on the first gate plate 3,
whereby the device 20 allows full flow of water through the
pipe.
[0068] FIG. 5 shows a device 30 with gate plates 3, 6, where the
connection assembly 31 comprises a second tension rod 32, a
guidance tube 33, a guidance strap 34 and the locking device 35
comprises a locking pin 36.
[0069] The second tension rod 32 is pivotally hinged to the second
gate plate 6 and connected to the guidance strap 34, which is
positioned between the two gate plates 3, 6, and the locking pin 36
is connected to the first gate plate 3.
[0070] An opening of the second gate plate 6 in the direction A
causes the second tension rod 32 to displace and disengage locking
pin 36 on the first gate plate 3, whereby the device 30 allows full
flow of water through the pipe.
[0071] The guidance tube 33 is mounted on the part of the second
tension rod 32, which is positioned between the guidance strap 34
and the second gate plate 6. Due to the fact that the guidance
strap 34 is attached to the jacket 2 in one position, the guidance
tube 33 prevents any opening of the second gate plate 6 in the
opposite direction A.
[0072] Turning to FIG. 6, a further embodiment according to the
invention is illustrated. In a pipe 37 a device 1 is inserted,
where the device comprises a jacket 2 which in line with the
embodiments mentioned above is suitable to be installed inside the
pipe 37.
[0073] Inside the jacket 2, first and second gate plates 3,6 are
arranged, which are pivotably mounted inside the jacket such that
the gate plates 3,6 may pivot about the axis 5,7. The gate plates
3,6 extend above the pivot points 5,7, and are in this embodiment
equipped with weights 410 which, due to the off-central location of
the weights 40 in relation to the plane of the gate plates 3,6,
will urge the gate plates against the direction indicated by the
arrow "B". The arrow "B" indicates the direction from which a
rodent will attempt to gain access into the pipe 37, and thereby
into the installations upstream from the device 1. Adjacent the
first gate plate 3, a pendulum member 41 is arranged. In the first
gate plate member 3, an aperture 42 is provided such that a section
of the pendulum member 41 in its rest position as illustrated in
FIG. 6 will penetrate the aperture in the first gate plate 3 such
that part of the pendulum member 41 will be on the back side of the
first gate plate member 3, and part of the pendulum member 41 will
be on the front side. A lower edge 43 of the pendulum member will,
in the rest position, engage the lower edge of the aperture 42
provided in a first gate plate member such that a mutual
interlocking between the two members is accomplished. In the
position as illustrated in FIG. 6, it is impossible to move the
first gate plate member 3 backwards or forwards in relation to the
flow direction of the waste water. In this manner, access is denied
for rodents and the like trying to gain access in the direction
indicated by the arrow "B".
[0074] The second gate plate member 6 is provided with a first
notch 44 such that as waste water flowing in a direction opposite
the direction indicated by the arrow "B", the second gate plate
member 6 will pivot about the axis 7 whereby the notch 44 will
engage the pendulum member 41, and push the lower edge 43 of the
pendulum member 41 out of engagement with the lower edge of the
aperture 42 provided in the first gate plate member 3 whereby the
locking engagement between the pendulum member 41 and the first
gate plate member 3 is released such that both gate plate members
3,6 may pivot in order to allow the flow of waste water to pass the
device according to the invention.
[0075] As a security measure, in order to avoid that an overflow of
waste water enters the mechanism and disturbs the proper
functioning of the mechanism as described above, a shield plate 45
is provided upstream of the pivoting mechanisms such that waste
water will be forced to leave the pipe member 37 by passing the
gate plates 3,6 below the extent of the shield plate 45.
[0076] In FIG. 7, a plane view of the first gate plate 3 is
illustrated wherein the aperture 42 may easily be recognised.
Obviously, the actual shape of the aperture may be different from
the shape illustrated, the important aspect relating to the
aperture being the fact that the pendulum member may engage an edge
of the aperture, and thereby create the mutual interlock between
the pendulum member 41 and the first gate plate 3.
* * * * *