Note: Descriptions are shown in the official language in which they were submitted.
CA 02206968 1997-06-04
TITT,~
FRONT STRUCTURE OF A RAILWAY ELECTRIC LOCOMOTIVE WITH A
RETRACTABLE DOOR FOR THE ACCESS TO THE AUTOMATIC COUPLER
DESCRIPTION
Field of the Invention
The present invention relates to a front structure of
a railway electric locomotive with a retractable door for
the access to the automatic coupler.
The automatic coupling device located in the front
side of modern railway locomotives must be housed inside
the front structure on account of aerodynamic and
aesthetic reasons. However, such coupling must be easily
and rapidly accessible to allow the various manoeuvres of
the locomotive to be performed. All the known systems
provide the presence of a front door with single or double
mobile panels which is opened when the access to the
automatic coupler is required. In such an occasion, the
door or its mobile panels keep on being opened and
protruding, even during running. In some cases, in
consequence of the shape of the front side of the
locomotive, it is impossible to make doors which also
allow both the lodging of and the access to the buffers,
and alternative technical solutions to carry out the same
function must be designed. Furthermore, the presence of
front doors very often breaks off the aesthetic continuity
of the front structure of the locomotive and causes
undesired limitations to its configuration.
Summary of the Invention
It is an object of the present invention to provide a
front structure of a railway loc-omotive suitable to
accomodate the automatic coupler so that it is not
normally in view and to make it accessible by means of a a
simple manoeuvre, when necessary.
A particular object of the present invention is to
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provide a new front structure of a locomotive of the type
described above comprising a door suitable to be kept in a
opened and a closed position, and equipped with a
displacement device for guiding its movement from one
position to the other using the manual action of an
operator.
Another object of the present invention is to provide
a front structure of a locomotive of the type described
above in which the opening and the closing manouvres of
the door can be carried out without requiring excessive
manual effort and without involving dangerous situations
for the operator.
A further object of the present invention is to
provide a front structure of a locomotive of the type
described above in which the displacement device is
suitable to withstand mechanical and aerodynamic loads
caused by train motion both with closed door as well as
open door.
These results are achieved with the front structure
for locomotives according to the present invention whose
characteristic consists in that it comprises a movable
door pivotally connected to said structure and
translatable within said structure so that it can be
arranged in a closed position and in a open position
angularly spaced of about 90~ with respect to said closed
position and retracted inside said structure.
In the preferred embodiment of the invention a door
displacement unit is provided for transmitting to the door
a substantially translational motion inside the structure
along the longitudinal axis of the locomotive, whereas the
rotatory motion of the door is manually performed by the
operator against the resistance of elastic means which
tend to keep the door in the closed position.
In particular, the door is hingedly suspended from
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the fixed part of the structure and is slidingly mounted,
along the edges of the front opening, to achieve its axial
translational motion.
Brief description of the drawings
Further characteristics and advantages of the front
structure of the locomotive according to the present
invention will become more apparent in the following
description of one of its possible embodiments, given as
an example and not limitative, with reference to the
attached drawings in which:
- figures 1, 2 and 3 are schematic side views of the
front structure of a locomotive according to the invention
in which the movable door is respectively in a closed
position, an internally translated position, and an opened
15 position;
- figure 4 is a plan view of a side of the front
structure of the locomotive according to the present
invention;
- figure 5 is a sectional side view according to
arrows V-V of figure 6;
- figures 6 and 7 show in partially sectional front
views of the right and the left side respectively of the
front structure of the locomotive according to the present
lnventlon.
Description of the preferred embodiment
With reference to figure 1, there has been indicated
at 1 an outline of the fixed front part of a railway
locomotive on which an opening la is formed, and at 2 a
movable front part, thereof hereinafter called "nose". The
movable front part or nose 2 has suc1~ a -shape that it can
be accomodated without discontinuity within opening la and
is pivotally connected at 3, to a floating frame 4 hinged
at 5 to an anchor plate 6 integral with fixed front part 1
of the locomotive. An arm 7, integral with nose 2, is
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connected to plate 6 by elastic means 8 urging against arm
7.
Sideways floating frame 4 a nose displacement unit is
provided, generally indicated at 9, fixed to the body of
buffers 10, which are mounted on the end sill (not shown)
of the locomotive. The displacement unit 9 is connected to
the floating frame 4 by connecting rod means 11.
As described in more detail in figures 4 and 5,
floating frame 4 has light metal box-shaped construction
and comprises an extruded tubular cross bar 12 with square
section and side-arms 13 and 14 which extend upwardly and
respectively downwardly from the two ends of the cross bar
12. The upper side-arms 13, which lean forward with
respect to the alignment axis with the lower side-arms 14,
are connected by means of pivots 5 to the respective
plates 6, which are fitted in the composite material of
the front of the locomotive, whereas the lower side-arms
14 are connected to plates 15 which are fixed to the sides
of nose 2 by means of pivots 3. From plates 15 arms 7
extend in a substantially axial direction, which are
connected to the respective plates 6 by means of elastic
means 8, made up in particular by air springs.
As shown in figures 4 and 5, the displacement unit 9
comprises two crank mechanisms 9a and 9b located near the
2s sides of the front part 1 and fixed connected to buffers
by means of supports 16 integral with them. Crank
mechanisms 9a, b are connected to each other by means of a
driven shaft 17, extending crosswise with respect to the
locomotive, in order to assure the synchronism of their
movements. Shaft 17 is oversized to such an extent as to
have both high stiffness as well as reduced weight.
A drive shaft 18 extends parallel to driven shaft 17
and comprises a tubular central part 18a and two end parts
18b made out from a solid bar, which engage with support
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16 and on which gear wheels 21 of a chain transmission 20
are keyed. Chain 20 engages with a second gear wheel 22,
keyed on a small actuating shaft 23. From the ends of
driven shaft 17 two radial plates extend which act as
rotating arms 19 for drive shaft 18 with respect to the
fixed part.
Small actuating shaft 23 is mounted on a support 24
integral with buffers 10. At the ends of tubular part 18a
of drive shaft 18 flanges are provided each of them
lo bearing protrusions 27 within which a corresponding radial
tooth 28 extending from driven shaft 17 is engaged. This
connection between drive shaft 18 and driven shaft 17
assures the transmission of the rotation between the two
shafts and a certain clearance (in particular about 30~)
between them, whose function will be explained
hereinafter.
For each end of drive shaft 18 a chain transmission
20 and a respective small actuating shaft 23 are provided.
At the end of each small actuating shaft 23 a small
opening 25 is provided on both sides of the locomotive so
that a drive key 26 can be inserted by the operator. Such
key presents a reference tooth 26a, in correspondance to a
notch, not shown, formed on a matching jig 25a before the
fixed small opening 25, so that key 26 can neither be
inserted nor extracted unless nose 2 is wholly closed or
wholly open.
Arms 29 extend radially and rigidly close to the ends
of driven shaft 17, and connecting rod means 11 engage on
such arms. Each arm 29 comprises, as shown in figure 6, a
pair of plates welded to driven shaft 17 and an
articulated joint 30 for the respective connecting rod is
provided at the end thereof. Each connecting rod 11 is
connected, with the other end, to lower side-arms 14 of
floating frame 4 by means of a joint 31 and comprises a
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strut 32 with a C-shaped lenght 32a to avoid interference
with drive shaft 18 during the motion of the connecting
rod, and a coil-spring mechanism 33 which assures the
extensibility of the strut itself. In such a way it is
possible to face small assembling defects which would
otherwise cause damages.
By operating small actuating shaft 23, as will be
said next, driven shaft 17 moves from a position situated
over drive shaft 18 and illustrated full-line in figure 5
towards the position, substantially overturned,
illustrated in dotted line and indicated at 17a in the
same figure. The angular displacement of the shaft 17 is
equivalent to 190~ to be at least 5~ beyond the dead
centers at the ends of the displacement, assuring this way
the irreversibility of the motion. Anyway, for further
safety a cam-roll mechanism is provided (see figure 5)
comprising a disk 34 integral with drive shaft 18 with two
notches 35 along its edge which are spaced along the
circumference of 190~. Inside the notches 35 a small roll
36 is engaged which is supported by a small arm 37
extending from support 16 and elastically abuting on the
edge of disk 34.
The device described above works in the following
way. Reference is made to figures 1, 2 and 3 where the
device is schematically shown respectively in a closed
position, in an intermediate backwardly retracted
position, and in a completely retracted, open position.
To open nose 2 key 26 is inserted into one of small
openings 25 situated on the two sides of front part 1 of
the locomotive. After a first idle rotation of the key for
an angle of about 50~, a following rotation of 360~ causes
a rotation of 190~ of drive shaft 18, given the existing
gear ratio . As a consequence of such rotation driven
shaft 17, carried by arms 19 and by the connection formed
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by protrusions 27 and tooth 28 engaged between them,
rotates of 190~ from a position substantially overhanging
drive shaft 18 to a position substantially below it,
whereas small roll 36 is engaged in one of the two notches
35 to stabilize the reached position. During this rotation
connecting rod 11 is trailed so that, in turn, it can
trail floating frame 4, thus translating of about 80 mm
the nose 2 integral with it inside the front part of the
locomotive. The translation occurs in a substantially
parallel way with respect to the longitudinal axis of the
locomotive because of the presence of a slide guide
working between nose 2 and fixed front part of the
locomotive itself. As shown in figures 1, 2 and 3, the
slide guide is formed by a pair of slides 41 (only one
shown in the figures) integral with nose 2 and spaced from
one another which are slidingly engaged with the edge of
opening la where internally protruding dowels 42 are
provided which engage, in turn, with seats 43 formed on
slides 41.
At this point nose 2 is in a backwards position with
respect to the fixed part and it is possible for the
operator to introduce his hand to push the nose downwardly
to overcome the reaction of air springs 8 which tend to
keep nose 2 up. The sizing of air springs 8 is such that
they balance the weight of nose 2 with slight margin
whereby the rotation is mildly hindered.
After nose 2 is rotated of about 90~, it is recessed
within the front part of the locomotive and the automatic
coupler is made accessible. Nose 2 must be kept firmly
blocked in its opened position up to the next closure
operation. To that end, as shown in particular in figures
5 and 6, a locking device is provided which comprises a
pair of pins 38 integral with nose 2 extending in mutual
alignment toward the inside of the nose, and a cam 39
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integral with small actuating shaft 23 to which pins 38
engage at the end of the rotation of 90~ of nose 2 inside
front part l of the locomotive. In practice, when rotating
along with nose 2, pins 38 abut against cam 39 which is
rotated backwards. At a certain moment the rotation of
nose 2 leads pins 38 beyond the profile of cam 39 which
moves backwards elastically, thereby locking pins 38. The
elastic member of cam 39 iS made up by two springs 40
(figure 4) coaxial with the driven gear wheel 21 of chain
drive 20. The action of the pivot 38 against the cam 39
causes a rotation of the small drive shaft 23 of about 50~
which, given the existing gear ratio with the drive shaft
18, causes a rotation of the latter of about 25~. However,
in view of the existing clearance between drive shaft 18
and driven shaft 17 due to the connection between
protrusions 27 and tooth 28 engaged therebetween, such
rotation does not cause any displacement of the shaft 17.
The closing also occurs in two steps. From the
operator point of view such closing requires only the
rotation of the key, since the rotation of nose 2 iS
driven by air springs 8. In fact, the first part of the
rotation of the key makes cam 39 rotate backwards, thus
releasing the pivots 38 of nose 2. This one therefore goes
upwards while rotating around joints 3 because of the
2s action of air springs 8, until slides 41 abuts against the
edge of opening la. Keeping the key on rotation
displacement unit 9 is actuated, and as a consequence of
an angular displacement of the driven shaft 17 of about
190~, connecting rod ll is translated as well as floating
frame 4 connected therewith, thereby nose 2 iS pushed
forward. During this motion, whereas slides 41 run on the
edge of opening la, dowels 42 are engaged with seatings
43, thus assuring the right placing of nose 2 with respect
to opening la of front part l of the locomotive. The
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possibility of extracting key 26 from small opening 25
assures that the closing position has been achieved.
Variations and/or modifications can be brought to the
front structure for railway locomotives with a retractable
door according to the present invention without departing
form the scope of the invention itself, as defined in the
appended claims.
