Note: Descriptions are shown in the official language in which they were submitted.
,
1
Switching machine for a railroad
The present invention concerns a switching machine for switching the position
of railway
tracks, the switching machine being of the type comprising:
- a frame, intended to be fixed relatively to a pair of stock rails of a
railroad switch,
- a
throw bar translatable relatively to the frame along a transverse direction to
throw a
pair of inner rails of the railroad switch, located between the stock rails,
from a
normal track position to a reverse track position, and from the reverse track
position
to the normal track position,
- a point detector bar, translatable relatively to the frame along the
transverse direction
between a normal detection position intended to correspond to the normal track
position of the inner rails and a reverse detection position intended to
correspond to
the reverse track position of the inner rails,
- an indication contact assembly, fixed relatively to the frame, comprising
at least one
switch,
- at least one detector bar follower, movable relatively to the frame between
a proximal
position, in which the detector bar follower acts on the switch, and a distal
position, in
which the detector bar follower is away from the switch, the detector bar
follower
being adapted to follow displacement of the point detector bar in such a
manner that,
when the point detector bar is in one of its normal and reverse detection
positions,
the detector bar follower is in a first position among the proximal and distal
positions
and, when the point detector bar is in an intermediary position between its
normal
and reverse detection positions, the detector bar follower is in the second
position
among the proximal and distal positions,
- an inhibiting element jointly movable with the detector bar follower
between a primary
position when the detector bar follower is in its first position and a
secondary position
when the detector bar follower is in its second position,
- a cam bar having a kinematic connection with the throw bar in such a
manner that
the cam bar and the throw bar are jointly translatable relatively to the
frame, the cam
bar comprising a tongue portion and being translatable relatively to the frame
along a
longitudinal direction (X) between an unlock position in which the tongue
portion is
able to be in contact with a stop of the inhibiting element, preventing the
inhibiting
element from reaching its secondary position, and a lock position in which the
tongue
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portion is away from the stop, allowing displacement of the inhibiting element
between its primary and secondary positions.
Such switching machines are known and are generally motor driven. An example
of
such a switching machine is the GRANDMASTER 4000 Switch Machine of ALSTOM.
In the known switching machines, there are generally two detector bar
followers, each
one being rotatable relatively to the frame around a respective rotation axis
and being
adapted to act on a respective switch of the indication contact assembly when
it is in its
proximal position, the detector bar followers comprising a first detector bar
follower which is
adapted to be in its second position when the point detector bar is in its
normal detection
position and a second detector bar follower which is adapted to be in its
second position
when the point detector bar is in its reverse detection position.
This structure allows the switching machine to detect when the inner rails are
in their
normal position, in their reverse position, and in an intermediate position
between their normal
and reverse position. Indeed, when the inner rails are in their normal or
reverse position, only
one of the switches of the indication assembly will be activated by the
detector bar followers;
this will inform the switching machine that the railroad switch is in a safe
configuration, and
the switching machine will emit a signal to inform the trains circulating on
the railroad that
they are allowed to cross the railroad switch. Furthermore, depending on which
switch is
activated, the switching machine will be able to conclude if the rails are
either in their normal
or reverse position. When the inner rails are in an intermediate position
however, either both
or none of the switches will be activated by the detector bar followers, thus
providing the
switching machine with the information that the railroad switch is not in a
safe configuration.
As a result, the switching machine will emit a signal to inform the trains
circulating on the
railroad that they shall not go through the railroad switch.
An additional element of the known switching machines is the lock bar, which
is
intended to lock the inner rails after the throw bar has switched them into
position. To that
end, the lock bar has notches formed therein and intended to receive a lock
lug of the cam
bar when the cam bar is in its lock position. When the inner rails are not
properly positioned at
the end of the movement of the throw bar, none of the notches formed in the
lock bar is
aligned with the cam bar, so that the lock lug cannot be received therein; the
cam bar can
therefore not reach its lock position and release the inhibiting elements. In
such a case, the
inhibiting elements block the detector bar followers in their first position
so that none of the
detector bar followers can move towards its second position, even if the point
detector bar is
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in its normal or reverse detection position. As a result, either both or none
of the switches will
be activated by the detector bar followers, thus providing the switching
machine with the
information that the railroad switch is not in a safe configuration, and the
switching machine
will emit a signal to inform the trains circulating on the railroad that they
shall not go through
the railroad switch.
As one can easily understand from the foregoing, detection by the switching
machine of
safe and unsafe configurations of the railroad switch depends on the
respective positioning of
the point detector bar and of the lock bar, a safe configuration being
detected only in the case
when both the point detector bar and the lock bar respect a precise
positioning relatively to
the frame and relatively to each other.
In order to maintain proper operation of the switching machine, monthly
inspection of
the point detection system is required. Since normal operation of the
switching machine
involves all components moving together, it is necessary to isolate desired
variables for this
test. To do this, traditionally the lock bar is forced out of proper
adjustment or disconnected
.. from the rails altogether such that the switching machine can indicate a
safe configuration of
the railroad switch even with an obstruction in the rail, when normal
operation of the lock bar
would have prevented such an indication to occur. The railroad switch is then
manually
thrown from one position to the next to determine that the contacts are
appropriately adjusted
and that the point detector bar is still properly driving the indication.
Everything must then be
replaced to its original state before maintainers can reinstate the railroad
switch and allow
trains through.
To disconnect or readjust the lock bar requires numerous large tools and
increases the
time that maintainers are on the track. This also increases the time that
trains are disallowed
through that section of track, and maintainers often have to wait for long
periods of time
before the track is scheduled to be clear long enough for their work.
Furthermore, failure to
properly restore the adjustment of all components could cause a failure of the
switching
machine, allowing false indications and potentially causing the derailment of
a passing train.
Accordingly, it is a primary object of the present invention to provide a
means of
disconnecting the function of the lock bar in the switching machine without
the need to
readjust it.
Another object of the present invention is to decrease the time it takes
maintainers to
prepare for the Point Detector Integrity Test.
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A further object of the present invention is to decrease the number of tools
required for
maintainers to prepare for the Point Detector Integrity Test.
Still another object of the present invention is to ensure the machine cannot
be remotely
operated while the Point Detector Integrity Test is occurring.
A yet further object of the present invention is to ensure the proper
adjustment of all
components in the switching machine is returned before the machine is operable
again.
To this end, the invention consists in a switching machine of the
aforementioned type,
wherein the inhibiting element comprises a main body relatively to which the
stop is vertically
translatable between an active position, in which the stop is in contact with
the tongue portion
of the cam bar when the cam bar is in the unlock position, and a passive
position, in which
the stop is away from the tongue portion of the cam bar when the cam bar is in
the unlock
position.
According to particular embodiments of the invention, the switching machine
further
comprises one or several of the following features, considered or alone or
according to any
technically possible combination:
- the inhibiting element comprises a biasing member biasing the stop toward
its active
position;
- the switching machine comprises a latch assembly to latch the stop in its
passive
position;
- the stop comprises a vertical shaft with a shaft body extending through a
hole formed
in the main body and, on top of the shaft body, a shaft head with a larger
diameter than the
diameter of the shaft body, and the switching machine comprises an actuation
device to
displace the stop between its active and passive positions, said actuation
device comprising a
plate assembly which is vertically translatable relatively to the frame, said
plate assembly
including a plate having a slot formed therein and through which the shaft
body extends, said
slot having a shape that follows the path of the shaft when the inhibiting
element is displaced
between its primary and secondary positions;
- the latch assembly comprises a latch with a front face and a protrusion
protruding from
said front face, said latch being rotatable relatively to the frame around a
horizontal axis
between a latching position, in which the protrusion extends within a
displacement region of
the plate assembly, and a liberation position, in which the protrusion is out
of the
displacement region of the plate assembly, the position of the plate assembly
when the stop
is in its passive position being above the position of the protrusion when the
latch is in its
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latching position, and the latch assembly further comprises a biasing element
biasing the
latch toward its latching position;
- the switching machine comprises a safety circuit to detect when the stop is
in its
passive position, said safety circuit comprising at least two stationary
contacts and at least
one mobile contact mounted on the plate assembly in a manner that, when the
stop is in one
of its passive and active positions, the mobile contact bridges the two
stationary contacts,
thus closing the safety circuit and, when the stop is in the other one of its
passive and active
positions, the mobile contact is away from the stationary contacts, thus
opening the safety
circuit;
- the switching machine comprises two detector bar followers, each one being
adapted
to act on a respective switch of the indication contact assembly when it is in
its proximal
position, the detector bar followers comprising a first detector bar follower
which is adapted to
be in its second position when the point detector bar is in its normal
detection position and a
second detector bar follower which is adapted to be in its second position
when the point
.. detector bar is in its reverse detection position;
- the stop of the inhibiting element of each detector bar follower is closer
to the inhibiting
element of the other detector bar follower when both inhibiting elements are
in their
secondary position than when both inhibiting elements are in their primary
position, and the
tongue portion of the cam bar has a median longitudinal axis which extends
between both
inhibiting elements;
- the point detector bar has a cylindrical surface in which a notch is formed,
the detector
bar follower is rotatable relatively to the frame around a vertical rotation
axis between its first
and second positions and has a follower part adapted for contacting the point
detector bar in
such a manner that, when the follower part is in contact with the cylindrical
surface of the
point detector bar, the detector bar follower is in its first position and,
when the follower part is
received in the notch, the detector bar follower is in its second position,
the main body of the
inhibiting element is rotatable relatively to the frame around a vertical
pivoting axis, and the
inhibiting element comprises a connecting rod connecting the detector bar
follower to the
main body; and
- the detector bar followers have a common biasing device comprising at least
one
spring having a first end attached to the main body of the inhibiting element
of the first
detector bar follower and a second end attached to the main body of the
inhibiting element of
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the second detector bar follower, said common biasing device biasing both
detector bar
followers toward their second position;
These and other features and advantages of the invention will be understood by
reference to the following description in conjunction with the annexed
drawings, wherein:
- Figure 1 is a plan view of a railroad switch connected to a switching
machine
according to the invention,
- Figure 2 is a plan view of a point detection system of the switching
machine of
Figure 1, wherein some components have been omitted to show hidden details,
- Figure 3 is a cross-section view taken along line of Figure 2,
- Figure 4 is a perspective view of some components of the point detection
system of
Figure 2, showing components which had been omitted in Figure 2, an inhibiting
device of the point detection system being shown in an active configuration,
- Figure 5 is a plan view showing the cam bar and the components of Figure
4 seen
from above,
- Figure 6 is a cross-section view of the components of Figure 5 taken
along line VI-
VI of Figure 5,
- Figure 7 is a perspective view of a portion of the inhibiting device of
the point
detection system of Figure 2,
- Figure 8 is a partially exploded perspective view of a plate
assembly of the point
detection system of Figure 2, and
- Figure 9 is a perspective view of a latch assembly of the point detection
system of
Figure 2.
The railroad switch 10 shown in Figure 1 has stock rails 12A, 12B and inner
rails 14A,
14B. A front rod 16 and a second rod 18 interconnect the inner rails 14A, 14B.
The inner rails
14A, 14B are movable relatively to the stock rails 12A, 12B between a reverse
position, in
which a first inner rail 14A is in contact with a first stock rail 12A, the
second inner rail 14B
being spaced from the second stock rail 12B, as shown in Figure 1, and a
normal position
(not shown), in which the first inner rail 14A is spaced from the first stock
rail 12A, the second
inner rail 14B being in contact with the second stock rail 12B.
The railroad switch 10 is operated by a switching machine 20 according to the
invention
and which comprises a throw bar 22, a lock bar 24, and a point detector bar
26. To that end,
the throw bar 22 is connected via a throw rod 28 to a rod connector 30 fixed
to the second rod
18, the lock bar 24 is connected via a lock rod 32 to a connector lug 34 fixed
to the front rod
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26, and the point detector bar 26 is connected via a connector rod 36 to a
point detector
attachment rod 38 which is fixed to one of the inner rails 14A, 14B.
The switching machine 20 comprises a fixed frame 40 elongated along a
longitudinal
direction X, and each one of the throw bar 22, lock bar 24, and point detector
bar 26 is
elongated along a transversal direction Y which is substantially perpendicular
to the
longitudinal direction X. The longitudinal and transversal directions X, Y
define together a
horizontal plane to which a vertical direction Z is perpendicular.
Each one of the throw bar 22, lock bar 24, and point detector bar 26 is
translatable
relatively to the frame 40 along said transversal direction Y. In particular,
the lock bar 24 is
translatable between a normal locking position (not shown) when the inner
rails 14A, 14B are
in their normal position and a reverse locking position (not shown) when the
inner rails 14 are
in their reverse position, and the point detector bar 26 is translatable
between a normal
detection position (not shown) when the inner rails 14A, 14B are in their
normal position and a
reverse detection position (not shown) when the inner rails 14A, 14B are in
their reverse
position.
Preferably, the switching machine 20 also comprises a motor (not shown) to
drive the
throw bar 22.
With reference to Figures 2 and 3, the lock bar 24 has a transversal groove 42
formed in
a front face of the lock bar 24, said groove 42 having a vertical flat bottom
joining an upper
face of the lock bar 24. The lateral extension of the groove 42 is limited, in
other words, the
groove 42 does not extend along the whole length of the lock bar 24.
The lock bar 24 has also locking slots 44 formed in a bottom face of the lock
bar 24,
each locking slot 44 emerging in a back face of the lock bar 24. The lateral
extension of these
locking slots 44 is also limited. They are positioned so that one of said
locking slots 44 is
substantially aligned with the longitudinal median axis M of the frame 40 when
the lock bar 24
is in its normal locking position and when the lock bar 24 is in its reverse
locking position.
The point detector bar 26 has a cylindrical surface 46 in which a notch 48 is
formed. It
should be noted that "cylindrical" shall here be understood in its broadest
sense, including
cases in which the cylindrical surface is not generated by revolution. In
particular, this notch
48 is formed by a section of the point detector bar 26 which has a narrower
diameter than the
rest of the point detector bar 26. The lateral extension of the notch 48 is
limited. The notch 48
is positioned so that it is substantially aligned with the longitudinal median
axis M of the frame
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40 when the point detector bar 26 is midway between its normal and reverse
detection
positions.
With reference to Figure 3, the switching machine 20 further comprises a cam
bar 50
lying at the bottom of switching machine 20. This cam bar 50 is elongated
along the
longitudinal direction of the frame 40 and it has a longitudinal median axis
which is
substantially collinear with that of the switching machine 20. The cam bar 50
has a kinematic
connection (not shown) with the throw bar 22 in such a manner that the cam bar
50 and the
throw bar 22 are jointly translatable relatively to the frame 40. One end of
the cam bar is an
oblong cam surface (not shown) which coordinates the movement of the throw bar
22 with the
motor, so that the cam bar 50 moves linearly along the longitudinal direction
from a lock
position to an unlock position and then back to the lock position during the
switching
operation. In the unlock positon, the cam bar 50 is at its furthest back
position, as shown in
the Figures and, in the lock position, the cam bar 50 is at its furthest
forward position in the
switching machine 20.
The cam bar 50 comprises a cam body 52, a lock lug 54 in the form of a block
attached
to the top surface of the cam body 52 at the far end opposite the cam surface.
This lock lug
54 is just low enough to slide through one of the locking slots 44 when the
lock bar 24 is in its
normal or reverse position and just tall enough to catch on the lock bar 24 if
said lock bar 24
is not in the ideal position.
The cam bar 50 further comprises a tongue portion 56 extending from a point of
the top
surface of the cam body 52. The tongue portion 56 consists in a flat, narrow
bar positioned
substantially parallel to the cam body 52 and substantially aligned with the
longitudinal
median axis M but raised to a higher vertical positon than the cam body 52 via
a block 58 at
the end of the tongue portion 56 oriented toward the cam surface. The end 60
of the tongue
portion 56 opposite the block 58 features 45 degree angled edges such that the
very end of
the tongue portion 56 is slightly narrower than the rest of it.
Coming back to Figure 2, the switching machine 20 also comprises a contact
assembly
62, two detector bar followers 64A, 64B designed to act on the contact
assembly depending
on the position of the point detector bar 26, and two inhibiting elements 66,
each one being
able to inhibit action on the contact assembly 62 of a respective one of the
detector bar
followers 64A, 64B depending on the position of the cam bar 50.
The contact assembly 62 comprises two push-to-open switch devices 70. Each one
of
these switch devices 70 is adapted so that, when a pressure is applied on this
switch device
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70, the switch device 70 opens a respective electrical circuit (not shown)
connected to said
switch device 70, so that the switch device 70 is said to be in an "off'
position. When the
pressure is released, the switch device 70 closes said respective electrical
circuit, so that the
switch device 70 is said to be in an "on" position. At least one of the switch
devices 70 needs
to be in an "on" position so that the switching machine 20 can detect that the
railroad switch is
in a safe configuration.
Each detector bar follower 64A, 64B is positioned on a respective lateral side
of the
longitudinal median axis M. It is positioned vertically above and clear of the
lock bar 24 while
being substantially at the same height as the point detector bar 26.
Each detector bar follower 64A, 64B is rotatable relatively to the frame 40
around a
substantially vertical rotation axis 72 between a proximal position, in which
the detector bar
follower 64A, 64B acts on a respective one of the switch devices 70, and a
distal position, in
which the detector bar follower 64A, 64B is away from said switch device 70.
The rotation
axis 72 of the detector bar followers are substantially transversally aligned
and are
transversally spaced away from each other.
Each detector bar follower 64A, 64B has a body 71 with an elongated, diamond
shape
overall with two acute-angle corners and two obtuse-angle corners.
The detector bar follower 64A, 64B crosses the vertical rotation axis 72 at a
pivot point
74 situated at one of the obtuse-angle corners. At the opposite obtuse-angle
corner is located
a correspondence pin 75 (Figure 3), protruding vertically from a lower surface
of the body 71,
said pin 75 being fixed to the body 71 and being adapted to engage the groove
42 of the lock
bar 24 when the lock bar 24 is in one of its normal and reverse locking
positions and the
detector bar follower 64A, 64B is in its distal position.
Thus, in case the lock bar 24 and the point detector bar 26 are out of
correspondence
with respect to each other at the end of a rail switching operation, one of
the detector bar
followers 64A, 64B will have its correspondence pin 75 resting on the lock bar
24 outside of
the groove 42 and will thus be prevented from reaching its distal position. As
a consequence,
both detector bar followers 64A, 64B will keep acting on their respective
switch devices 70, so
that the switching machine 20 will not be able to indicate a "safe condition"
of the railroad
switch until the situation is corrected.
At one of the acute-angle corners a roller 76 is positioned, adjacent to the
point detector
bar 26, and forms a follower part intended to be in contact with the point
detector bar 26. At
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the opposite acute-angle corner is an attachment point 78 which is rotatably
attached to an
end of a respective one of the inhibiting elements 66.
Each detector bar follower 64A, 64B further includes a switch arm 80
protruding from a
top surface of the body 71 and extending substantially horizontally away from
the follower
part 76. The switch arm 80 has a free end 82 opposite the body 71 with a
roller defining the
contact surface of the detector bar follower 64A, 64B with the respective
switch device 70
when the detector bar follower 64A, 64B it in its proximal position.
The respective positions of the follower part 76 and of the switch arm 80 are
adapted so
that, when the follower part 76 is in contact with the cylindrical surface 46
of the point detector
bar 26, the detector bar follower 64A, 64B is in its proximal position and,
when the follower
part 76 is received in the notch 48 of the point detector bar 26, the detector
bar follower 64A,
64B is in its distal position.
Furthermore, the respective positions of the detector bar followers 64A, 64B
and of the
point detector bar 26 are adapted so that reception in the notch 48 of the
follower part 76 of a
first one of the detector bar followers 64A is possible only when the point
detector bar 26 is in
its normal detection position, so that reception in the notch 48 of the
follower part 76 of a
second one of the detector bar followers 64B is possible only when the point
detector bar 26
is in its reverse detection position, and so that none of the follower parts
76 of both detector
bar followers 64A, 64B can be received in the notch 48 without unmounting the
switching
machine 20 when the point detector bar 26 is in its intermediary position.
Each inhibiting element 66 is positioned on a respective lateral side of the
longitudinal
median axis M. It comprises a main body 84 which is pivotally mounted on the
frame 40
around a substantially vertical pivoting axis 86 between a primary position
shown in Figure 2
and a secondary position (not shown). This pivoting axis 86 is nearer from the
longitudinal
median axis M than the rotation axis 72 of the respective detector bar
follower 64A, 64B.
With reference to Figure 3, the main body 84 comprises a vertical pivot shaft
88 and two
horizontal arms 90, 92. The pivot shaft 88 is vertically aligned with the
pivoting axis 86 and
cooperates with a corresponding vertical pole (not shown) fixed to the frame
40 to allow
rotation of the main body 84 relatively to the frame 40. The arms 90, 92 are
vertically aligned
and are vertically spaced away from each other, a top arm 90 extending
substantially
horizontally from a top end of the pivot shaft 88 and a lower arm 92 extending
substantially
horizontally from a lower end of the pivot shaft 88. In particular, the top
arm 90 is positioned
above the tongue portion 56 of the cam bar 50, and the lower arm 92 is
positioned under said
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tongue portion 56. Each arm 90, 92 has a free end 94, opposite the pivot shaft
88, provided
with a hook.
Each inhibiting element 66 further comprises a stop 96 mounted on the main
body 84 so
that it follows the same horizontal displacement as the main body 84. This
stop 96 is
positioned so that it is able to abut against the tongue portion 56 of the cam
bar 50 when the
main body 84 is in its primary position and the cam bar 50 is in its unlock
position, and so that
it is away from the tongue portion 56 of the cam bar 50 when the main body 84
is in its
primary position and the cam bar 50 is in its lock position.
Each inhibiting elements 66 is articulated so that its stop 96 remains on a
same lateral
side of the longitudinal median axis M between the primary and secondary
positions of the
main body 84, the stop 96 being closer to the median longitudinal axis M when
the main body
84 in its secondary position than when the main body 84 is in its primary
position. Thus, the
median longitudinal axis M extends between the stops 96 of the inhibiting
elements 66
whatever the position of these inhibiting elements 66, and these stops 96 are
closer to each
other when the main bodies 84 of the inhibiting elements 66 are in their
secondary positions
than when these main bodies 84 are in their primary position. This has the
consequence that,
when the cam bar 50 is in its unlock position, its tongue portion 56 prevents
the inhibiting
elements 66 and thus the main bodies 84 from reaching their secondary
positions. However,
when the cam bar 50 is in its lock position, its tongue portion 56 being away
from the stops
96, displacement of the inhibiting elements 66 between their primary and
secondary positions
is allowed.
As a consequence, in case the lock bar 24 and the point detector bar 26 are
out of
correspondence with respect to each other at the end of a rail switching
operation, the lock
bar 24 preventing the cam bar 50 from reaching its lock position because the
lock lug 54 is
not able to engage one of the locking slots 44, both stops 96 will abut
against the tongue
portion 56 of the cam bar 50, thus preventing both detector bar followers 64A,
64B from
reaching their distal positions. Both detector bar followers 64A, 64B will
therefore keep acting
on their respective switch devices 70, so that the switch machine 20 will not
be able to
indicate a "safe condition" of the railroad until the situation is corrected.
Each inhibiting element 66 is jointly movable with its respective detector bar
follower
64A, 64B so that its main body 84 is in its primary position when the detector
bar follower is in
its proximal position and in its secondary position when the detector bar
follower 64A, 64B is
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in its distal position. To that end, each inhibiting element 66 comprises a
connecting rod 98
connecting the main body 84 to the respective detector bar follower 64A, 64B.
This connecting rod 98 is attached at one end to the respective detector bar
follower
64A, 64B via the attachment point 78 described above, and at the other end to
the top and
lower arms 90, 92 of the main body 84 via rotatable connections 99 which are
further away
from the pivot shaft 88 than the stops 96.
The connecting rod 98 extends substantially parallel to the point detector bar
26, from
the attachment point 78 toward the longitudinal median axis M.
Advantageously, the connecting rod 98 is adjustable in length.
The switching machine 20 further comprises a biasing device 100 biasing the
detector
bar followers 64A, 64B toward their distal positions. This biasing device 100
comprises two
extension springs 102, each one having a first end attached to the main body
84 of a first one
of the inhibiting elements 66 and a second end attached to the main body 84 of
a second one
of the inhibiting elements 66. in particular, a first one of the springs 102
has its ends attached
to the hooks provided at the free ends 94 of the top arms 90 of both main
bodies 84, and a
second one of the springs 102 has its ends attached to the hooks provided at
the free ends
94 of the lower arms 92 of both main bodies 84.
The two springs 102 are therefore stretched horizontally between the arms 90,
92 of the
two main bodies 84, roughly parallel to the point detector bar 26. These
springs 102 thus
work to draw the free ends 94 of the arms 90, 92 toward each other, biasing
these main
bodies 84 toward their secondary positions. This has the consequence that the
connector
rods 98 of both inhibiting elements 66 are pulled toward each other, these
connector rods 98
thus applying a biasing force on the detector bar followers 64A, 64B, at the
attachment points
78, this force biasing the detector bar followers 64A, 64B toward their distal
position.
Turning now to Figures 4 to 7, there is shown that the stop 96 of each
inhibiting element
66 (even though only one of these inhibiting elements 66 is shown of these
figures, the other
one is the symmetrical counterpart of the shown inhibiting element 66)
comprises a mobile
shaft 104 and a roller 107 attached at a lower end of said mobile shaft 104.
The mobile shaft
104 has a shaft body 105 extending substantially vertically through a hole 106
in the top arm
90 of the main body 84 and, at the top of said shaft body 105, a flat, round
head 108. The
stop 96 is therefore vertically translatable relatively to the main body 84
between an active
position, shown in Figures 4 and 7, in which the stop 96 rests on the lower
arm 92 of the main
body 84, and a passive position, shown in Figures 3 and 6, in which the stop
96 is at distance
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from the lower arm 92, said distance being greater than the thickness of the
tongue portion 56
of the cam bar 50. When the stop 96 is in its active position, the roller 107
is able to be in
contact with the tongue portion 56 of the cam bar 50 when the cam bar 50 is in
the unlock
position, thus hindering displacement of the main body 84 toward its secondary
position, and,
when the stop 96 is in its passive position, the roller 107 is not able to be
in contact with the
tongue portion 56 of the cam bar 50 even when the cam bar 50 is in the unlock
position, thus
allowing displacement of the main body 84 toward its secondary position even
when the cam
bar 50 is in the unlock position.
A compression spring 109 is also mounted coaxially on said mobile shaft 104
between
the hole 106 and the roller 107 with a washer (not shown) between the spring
109 and the
roller 107 so that it acts as a biasing member biasing said stop 96 toward its
active position.
The switching machine 20 further comprises an actuation device to move the
stops 96
of the inhibiting elements 66 between their active and passive positions. This
actuation device
comprises a plate assembly 110 which is vertically translatable relatively to
the frame 40 in a
displacement region constituted by the space extending vertically above and
under the plate
assembly 110.
This plate assembly 110 comprises a bottom plate 112 and a top plate 114
connecting
the mobile shafts 104 of both inhibiting elements 66.
With reference to Figure 8, the bottom plate 112 comprises a slot 116 through
which the
shaft bodies 105 of the mobile shafts 104 extend. Said slot 116 is a
symmetrical shape
specially designed to allow the mobile shafts 104 to move normally during
normal operation.
As such, said slot 116 has a swept shape that follows the path of the mobile
shafts 104 when
the main bodies of the inhibiting members 66 are pivoted between their primary
and
secondary positions.
Extending along the bottom planar edge of the slot 116 is a ridge 118 on which
the
round heads 108 of the mobile shafts 104 are adjacent. The height of the slot
116 above the
ridge 118 is sized such that the heads 108 of the mobile shafts 104 have
enough room to
move between the bottom and top plates 112, 114 without excessive friction
preventing
motion.
The top plate 114 comprises an oval slot 120 with no ridge such that it
sandwiches the
shaft heads 108 when connected to said bottom plate 112 without pressing on
said shaft
heads 108. Said slot 120 is just narrower than the heads 108 of the mobile
shafts 104 such
that it forms a lip to hold the mobile shafts 104. The bottom and top plates
112, 114 each
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feature a pair of two holes 122, with the top plate 112 featuring a cutout 124
around said
holes 122.
These bottom and top plates 112, 114 are held together via a vertical handle
126, which
also acts to enable maintenance personnel to lift the aforementioned plates
112, 114. Pulling
said handle 126 up pulls the mobile shafts 104, thereby lifting the stops 96
and compressing
the springs 109.
The handle 126 is in the form of a round bar, bent at 90 degree angles 128 in
two
places, with a length 130 at each end that is of a smaller diameter than the
main bar 132 such
that a lip 134 is formed where the smaller diameter end 130 meets the larger
diameter main
bar 132. The smaller ends 130 are inserted through the holes 122 in the bottom
and top
plates 112, 114, with the lip 134 abutting against the top surface of the
cutout 124 on the top
plate 112. Bolts 136 are threaded onto the ends 130 of said handle 126 to hold
the top and
bottom plate 112, 114 together against the lip 134 and to hold said handle 126
to said plates
112, 114.
The top plate 114 also comprises two arms 140 extending horizontally toward
the front,
each with a metal mobile contact 142 mounted to the underside via a rivet 144.
Each mobile
contact 142 is in the shape of an inverted V with a flat bottom 146. These
mobile contacts 142
are part of a safety circuit which must be closed for remote electrical
operation of the
switching machine 20 to take place, said safety circuit further comprising
stationary contacts
148 (Figure 5) mounted to the top of a back plate 149 (Figure 6) which is
fixed relatively to the
frame 40. These mobile contacts 142 are positioned so that, in the active
position of the stops
96, they each bridge two of the stationary contacts 148 to close the safety
circuit and, in the
passive position of the stops 96, they both are away from the stationary
contacts 148, thus
letting the safety circuit open. Maintainers' safety from sudden switch
machine operation
which could be triggered by a remote dispatcher is therefore ensured when the
stops 96 are
in their passive position.
Returning to Figure 4 to 7, the switching machine 20 further comprises a latch
assembly
150 for locking the plate assembly 110 in place.
With reference to Figure 9, this latch assembly 150 comprises a latch 152
having a flat
vertical shape and mounted on a horizontal shaft 154 with a torsion spring 156
onto a bracket
158, said bracket 158 being fixed relatively to the frame 40. In particular,
the bracket 158
features a pair of holes 160 for mounting to the pivot shafts 88 of the main
bodies 84 of the
inhibiting elements 66.
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The latch 152 comprises a front face 161 and a protrusion 162 protruding from
said front
face 161, the protrusion 162 having a top face 164 and a bottom face 166.
These two faces
164, 166 are not quite parallel. If the top surface 164 is said to be
horizontal, the bottom
surface 166 angles up slightly so as to be in the correct position for holding
said plate
assembly 110 either up or down.
This latch 152 is rotatable relatively to the frame 40 around the horizontal
shaft 154
between a latching position, in which the protrusion 162 extends within the
displacement
region of the plate assembly 110, and a liberation position, in which the
protrusion 162 is
excluded from said displacement region.
The position of the plate assembly 110 when the stops 96 are in their passive
position is
above the position of the protrusion 162 when the latch 152 is in its latching
position, and the
position of the plate assembly 110 when the stops 96 are in their active
position is under the
position of the protrusion 162 when the latch 152 is in its latching position.
The top face 164
of the protrusion 152 constitutes a resting surface on which the bottom plate
112 rests when
the stops 96 are in their passive position, thus preventing the stops 96 from
coming back to
their active position, and the bottom face 166 constitutes a pressing surface
which rests on
top of the top plate 114 when the stops 96 are in their active position, thus
preventing the
stops 96 from being dislodged from their active position.
The front face 161 of the latch 152 comprises a flat front portion 168 just
below the
protrusion 162. This flat portion 168 pushes against a back side of the plates
112, 114 when
the stops 96 are in their active position, so that the spring 156 does not
lose tension. The
front face 161 further comprises a curved front portion 170 below the flat
portion 168; this
curved front portion 170 is designed to prevent collision with the top plate
114 when the stops
96 are in their active position.
The latch 152 further comprises an angled area 172 at its top, above the
protrusion 162,
and a spring rest area 174 at its back, behind the curved front portion 170.
The angled area
172 functions as a handle to pull said latch 152 out of the way to lift the
handle 126 when the
stops 96 are in their active position. The spring rest area 174 consists in a
slot receiving a
part of the torsion spring 156.
The torsion spring 156 acts as a biasing element biasing the latch 152 toward
its
latching position. To that end, the torsion spring 156 features two tail ends
176, which go into
small holes located at the outer edge of the bracket 158, and a middle loop
178 which applies
pressure to the spring rest area 174 to hold the latch 152 into positon up
against the
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aforementioned plate assembly 110. Thus, when the latch 152 is pulled to
rotate back, the
torsion spring 156 is tightened, increasing the spring tension. The torsion
spring 156 is also
adapted to provide consistent rotational pressure into the latch 152.
Thanks to the invention described above, preparing the switching machine 20
for the
Point Detector Integrity Test is facilitated. Indeed, to disconnect the
functions of the point
detector bar 26 and of the lock bar 24, the maintainers merely need to
displace the stops 96
toward their passive position by pulling the handle 124 up while pushing on
the angled area
172 of the latch 152. When the handle 124 has been pulled up, the latch 152
will return in its
latching position, thus insuring that the stops 96 remain in their passive
position.
There is in particular no need to disconnect the lock bar 24 or the point
detector bar 26
from the rails 14A, 14B, and therefore no need to readjust the position of
these bars 24, 26
relative to the rails 14A, 14B after the switching machine 20 has been tested.
Indeed, since,
when the stops 96 are in their passive position, displacement of the main
bodies 84 between
their primary and secondary positions is no longer conditioned on the cam bar
50 being in its
-- lock position, i.e. the positioning of the lock bar 24 relative to the came
bar 50 and notably of
the lock lug 54 relative to locking slots 44 does not limit the movement of
the main bodies 84
between their primary and secondary positions, actuation of the contact
assembly 62 by the
detector bar followers 64A, 64B is consequently not conditioned on the lock
bar 24 having
reached its normal or reversed position: the point detector bar 26 is thus
isolated from the
lock bar 24, so that a test can be run without both the point detector bar 26
and the lock bar
24 respecting a precise positioning relatively to the frame 40 or relatively
to each other. As a
consequence thereof, the number of tools is decreased, as well as the time
spent by the
maintainers to realize the Point Detector Integrity Test. Furthermore, there
is no risk that the
components of the switching machine 20 are not returned to their proper
adjustment after the
-- test.
In addition, the switching machine 20 provides enhanced security to the
maintainers,
since remote operation of the switching machine 20 is impossible when the
stops 96 are in
their passive position, which condition is necessary for the Point Detector
Integrity Test to be
conducted. There is therefore no risk that the maintainers are injured by a
displacement of
-- components of the switching machine 20 caused by a remote operation of the
switching
machine 20 during the test.
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